Can't figure out the SO number on my fender tag. Looked and Looked at 5 different decoders.

What? Clarify what You mean, only '64 cuda's got gold paint? What early Darts came with gold, 'cause My black '64 GT 'vert came with a matching pair of OE gold fenders on it, the black take-offs were there & I threw them in the truck as well....
Sure.

According to the little white book, Paint coda A is Gold in 64 and was for Barracudas only.

Chrysler had paint code U for Embassy Gold Metallic

Dodge and the 880 had paint code Z, which was Anniversary Gold Metallic.