need some gmc vin help

[made2drag]

i have a 67 small window gmc

i was reading some posts and saw a vin decoder. i tried to decode mine and it just doesnt add up. maybe someone here can help. dont have access to posting photos at the moment but here is the info.

my glove box spid shows: CS 1590D C 9705


my door jamb shows: CS1590D PC9705A


i figured out c for conventional and s for six cyl and 1 for 1/2 ton, anyone have any idea about the rest. thanks