It looks pretty much as the trimtag sections.
Here is were I got the numbers from
http://www.chevellestuff.net/1966/ch...s/66_codes.htm
1XD X=A31 Power windows D=C06 Power Top Convert
2MS M=M35 Transmisson (PowerGlide) S=U73 Manual antenna
5Y Y=A39 Belts All deLuxe
C 2 Paintcode C=Ermine White 2=Black
729 Is the interior Dark Blue,Medium Blue Imitation Leather
All this would match the TrimTag.
Jan