Decoding ID Plate

[jocko]

7500 is the GVWR for a 3/4 ton truck; 127 is the wheelbase for a long bed truck (but I assume you're probably more interested in the other codes)

521 is solid white paint (note this is not the ivory paint that was the standard secondary color in a conventional two tone, it's a bright white; standard interior color would have been fawn).

Z62 is the Custom Comfort Option trim code which includes left armrest, right sunshade, chrome cig lighter, full depth foam seat, special insulation, and right door lock.

Being a 66, it should have a SPID, which should also replicate some of this info - do you have a pic perhaps? Would love to see pics of the SPID and the truck.