That's a possible line of thinking.. could you tell if it was painted under the tag? Wonder if they ran out of proper rivets around Christmas.. my Dad's Charger had a factory dash mount screw issue that another members car had, again around the turn of the new yearAll Hemi cars built before the end of December, or more likely Christmas, were badged HP2.
As I noted my tag had round rivets in it as well. Assume it was popped and put back on during exterior painting. I just found it interesting that Bleep Bleeps car doesn't appear to have been painted on the jams and thought that just maybe they were using round head rivets on the line in 65.