I pulled off the buck tag and cleaned it tonight. Also removed the horns and gotta clean them too. A lot of old paint and dirt.
Ok, who can tell me what these mean? I found some info on WCCC site…
309
1DG
PB = Power Brakes. I find it interesting their isn’t a PS for power Steering on there too?
RM = Remote Mirror
EC = Emissions Controls (It’s a CA car)
S2
and I think that’s an R2 on the far right???
309 = Rotation number. Your car was #309 down the line on the day it was built
1DG = Interior Decor Group. The nicer standard interior.
PB = Power brakes. I don’t think Power Steering showed up on the Buck tag.
RM = Remote Mirror
EC = Emissions Controls (It’s a CA car)
S2 = An inspectors stamp
R2 = Also an inspectors stamp
Note, I may have some wrong but an confident of what I stated is correct.
Only one little correction 
That rotation number was for the first “half” of the cars build the bucking and body/trim part. The numbers didn’t start over at the “beginning of the day” they just repeated after the last series was used starting with 001. The numbers used in the series differed depending on year and plant.
Good pic, thanks for sharing!
The only thing I have to add is that (my understanding is) the Buck Tag only has codes for things that require the “buck guys” to punch holes or do modifications of some sort in order for an option to be installed.
So Power Brakes probably required a hole of some sort for proper installation, while Power Steering did not.
Same for the side mirror ~ specific punch-outs / hole cuts for routing the mirror controls.
They didn’t want to make any holes after painting where the area was exposed to water. The Buck tag was there to show operations done before priming and paint.
Maybe this should be in the trivia section, but why is it called a buck tag?
PS didn’t need to be noted since there was only one style/version of the drivers side inside front frame rail so all had the holes to begin with. The installation of the nut-serts must have taken place later and workers used another resource (such ad the buildsheet) to determine that need.
Dealt with the “bucking” of the unibody. Assembling the initial panels as a single unit that would later become a complete car is my understanding
Just posted the following over on the CJ site in response to a request and I thought it might help others over here so just cut and pasted - less the explanation of that individuals codes
These tags (when used/installed) were guides to the workers building the uni-body of these cars and helped them determine what holes needed to be present, brackets installed, and panels chosen to support different models, body types and options. San Jose only used them for a short period in 69 and in 70 while the coding is very different fron the other plants. Plant managers have told us that the codes would sometimes change on the fly during production but this didn’t happen too often. Because of this I would not suggest the use of a decoder that does not separate out the codes by year and plant. I would suggest you use Kevin Marti’s The Mustang and Cougar Tagbook. Helpful in decoding and understanding all sorts and kinds of tags found on these cars. You will notice that each relates to additional holes or brackets when compared to a more standard model
The rotation number was just a sequential number used to identify a body in a run of cars and the numbers would start back over (001) when ever the end of the sequence was reached no matter the day or time of day it was reached. Not at the beginning of every day. Length of the sequence depended on the plant and production year most often during the classic years it was 001-999. A second rotation number was assigned to the second half of production during the final part of assembly. That number would be the one in the upper left of the buildsheet.
You should recognize most of the coding on the upper two lines of your buck tag as coding matches your door tag or label.
As I recall it the buck was sort of the jig that the uni-body was assembled on. Before unibody construction the body rode on the buck until it was married to the frame / chassis. Once the basic shell was built in body / trim it came off the buck and started on the conveyor, the buck was returned to the body shop. I recall seeing defective Jeep CJ bodies still on the buck in the top floor of the Toledo plant.
The assembly process may have started on a “carousal”. A large fixture like a turn table where the fixture rotated in the center of workers each adding a panel or a series of welds. Often sub assemblies (headers, doors…) were assembled this way then added to the body.
Sorry don’t have pictures of the first panels going together. Do have the headers & cowl area being put together for another Ford model but that is posted and paid for on the other site.
Just for the heck of it - at least on some of the years we have pictures of roof panels were the last or one of the last panel to be added to the unibody for some reason
Sorry for getting off thread 
Can someone pls advise where this tag was mounted. I don’t have a photo of where mine was when I got the car
All the ones that I have taken off were painted black. I think that was done so that they did not stand out against the black of the radiator support.
Randy Goodling
CCOA #95
Might have been a secondary reason since Ford/Mercury took steps to hide other details by blacking them out. But we need to remember that after the body bucking process there was really no need/use for them and that they were attached to guide that process before paint was applied so painting them along with the panel they were attached to just made it easy and simple.
The buck tag is located on the radiator core support on the upper right side next to where the painted fender support overlaps the core support.
Thanks guys, mine doesn’t have a hole there but one on the right hand side instead.
Should the hole be where that dint is on the left?
[attachment=0]buck2.jpg3.jpg[/attachment
Brett, based on the “before” pic you posted, I believe the hole for your buck tag is behind where the fender overlaps the radiator support. In your old pic you can see what looks like a U-clip for the fender bolt, maybe? Fairly common for them to be partially covered by the fender overlap. Here you can see mine has the bolt and fender in place, with the tag screw over a smidge further than yours.
I hope that helps!
Thanks Mike, All good mate I put it where it should be now.
