1967-69 Barracuda Registry
29/30 have a 9 and a 0 punched, and 31 has a 1 punched.
Paint codes don't use all the letters, ie: there is no II1, but the IBM punch card does.
Pic of how the IBM punch card 'punches' the various characters.
On the Chrysler IBM card, the first 2 rows above 0 are R and X.
The 3 divisions of letters are 1-9, but there are only 26 letters, I forgot that the 3rd division begins at 2 so they all end at 9.
I imagine the thought process was probably to start each section with 9 and count backwards, so you always 'end' with 9 and never get to zero.