I am installing new brake lines in my 1969 XR7. The bolt that mounts the proportioning valve to the brass distribution block protrudes through a whole in the fender wall. See attached photo. Does this whole get filled, left as is or is the bolt too long and a body plug is inserted in the hole?
That appears to be the original configuration.
Two holes for attaching and one hole for the locator
Often this area would be covered with a coat of sound deadener applied over the black paint applied to the panel and after the car was just about completely assembled so that the product would seal gaps and such for water protection and deadening of “road noise”