B3I =
E6C =
GAM = VEHICLE - GOVERNMENT (G.S.A SALES)
TEJ = DISCOUNT - DEALER ALLOWANCE, ADMINISTRATIVE
TFD = SALES INCENTIVE - RETAIL AMENITIES - DELETE
YD3 = AXLE - (BASE EQUIP) FOR SCHEDULING GVW PLATE
1Q8 = Vehicle Inspection - GSA Form 1398
I have no listing for B3I, but B31 = COVERING FLOOR - VINYL, FRT, FULL WIDTH.
For E6C I have = COUNTRY - GAMBIA
You may want to check the "E6C" and see if maybe one of the digits is wrong.
I have a PDF file of the actual GM list of RPO codes that I can e-mail to you if you want it... just let me know. Don't post your e-mail addy here or you will get tons of spam. Just click on my user name, then click "View Public Profile" then click "Send a message via email to divorced". Tell me you want the list and I'll try to return the email with the list as an attachment. It should work that way, let me know if it doesn't. The list doesn't cover older stuff like my '72, but does include most newer stuff.