I've done my share of research about the 'birds and while I'm not making myself out to be an expert...I do know that decal colors varied on certain body colors.
There was Chrysler documentation about how they "should" have been....as seen above...but we also have to think about how the cars were built.
When these cars were built, they weren't built as "collectibles". The assembly personnel were just sending cars out the door. In my opinion, it would be very easy to have the "wrong" color decals on a car...and who would care? Well, as long as they were the same color on both sides!
Now, 40 years later we all seem to think things on these cars are absolute. I know from the cars I've restored...the exception is the rule.