I tracked these down from a guy in Ohio who had them for years... the envelope is postmarked 1974 and the label reads "69 427 Yenko Super Camaro". I actually have a copy of one of the photos already but 3 of them I have never seen before. They are shots of the gold magazine road test car, and the one with the mag wheels appears to have been taken at the track during the day of the test. The other shot appears to be the same car wearing rally wheels and an inventory tag in the drivers side window... looks to have been photographed in Chicago(!?) Seems this car got around. Just thought I'd share.
Heres the envelope...