Unusual Color on 1966 Barracuda

Reviving an old thread. I run the 1966-67 Charger Registry (former owner of a mauve 1966 Barracuda, 1971 Dart Swinger and 1974 Dart Swinger) and am helping a guy with his 999 code 1966 Barracuda fender tag.

I have found four other fender tags online for 999 1966 Barracudas. All have the E1 code for cleaner air package. Are there more 1966 Barracuda 999 tags out there and possibly all of them have this E1 code? Thanks!

Tags I've found:
51340373
5?340443
52740500
5??40371