Some thoughts on the question Bill started here. I believe the photo he posted is the COPO Camaro I restored and recently was sold at Mecum Indy.
the reason I used the bright fasteners on the front WW moldings was based on three things.
1st., In talking to a well known Camaro restorer a few years ago he asked me if I had ever seen a original 69 Z21 car with the bright fasteners, I had not, he said he had taken apart a few with the bright fasteners. He even mentioned the marks left in the moldings from the serrated washers.
2nd., This prompted me to look in the 69 Camaro AIM. re; UPC Z21, item #4 GM# 3853846,(AMK B-10900 on pg 103 of there pdf catalog.) added by revision 4 dated 10/86. Also note rev #5 on the line under R4, the note "existing screws removed. So based on this it appears the intent was to use the bright fastener, however as we know we have seen both. And it may not be consistent even on later cars ?
Maybe a good research topic ? Some of you may have old moldings off your cars and can at least check for the washer marks ?
3rd., I wanted to stir some debate :>) "Never say never"
Thanks Mike