Seems like most people don't use the bumper fillers since they close the gap between the bumper and fender to the point where its not seen or needed. First I heard that 67 had metal ones.

I think i had like 3 or 4 of the factory rubber ones but only for one side and the other side where all junk. I used the crap aftermarket plastic ones from classic industries. They really suck. The issue is they they are a hard plastic and your limited to how close you can put the bumper to the fender.

I read in the archives here that the factory put the space in the bumper so if the bumper got taped it wouldn't chip the paint on the fender.