Thanks Russ! Knowing who these companies are is a big part of the battle won. The other half is determining which of these companies actually supplied fasteners to GM during the First Gen run... and which ones are correct for each individual year. From what I've gathered so far, many of the same fasteners have been observed on both 67's & 68's. As for the 69, it too has many fasteners used during the first two years but a few appear to be unique to only the 69.
Here are the head marks John mentioned. Those highlighted in red are the ones we've managed to find so far (he also mentioned there are others, many, many more...); TR, UR, RBW, RSC, E, EL, F, AD, D, WB, L, LS, LE, C, M, ANCHOR.
If anyone is positive any of these are or are not factory First Gen fasteners (pictorials) please let us know so we can either keep them or cross them off.
Here are all the pages with numbers for each head-mark...numbering each one should help for future reference (sorry Russ I should have done this from the get-go).