Here's a couple more to add ...
My 77 GMC Sierra:
And Dad's 77 GMC Sierra Classic:
A few things I noticed when comparing the two:
(1) Both trucks were equipped with factory dual exhaust but it's only listed on the SPID in mine. That's because (according to the 77 truck info kit from the GM Heritage Center) it was automatically included with the LF4 400 engine in Dad's truck.
(2) Both trucks were also equipped with the Z53 gauge cluster but again, it's only listed on the SPID in mine. Turns out that's included with the YE9 Sierra Classic Equipment. And I also found it interesting that it was still being listed as "GAUGES - AMMETER, OIL" even though these trucks changed over to voltmeters in 76.
(3) My 77 was built in Oshawa and Dad's was built in Flint. As a result, you can see some variations in the way they were typed up. Like how the "MODEL TK10903" is listed. And how the option numbers on mine are lined up near the right side of the column, while on Dad's they're aligned to the left of the column (and have a 1 prefix).
(4) Finally, they are both GMC's but neither one of them has the Z88 "GMC Conversion" code as described in this thread -->
http://67-72chevytrucks.com/vboard/s...=621909&page=2
I guess some assembly plants just didn't bother listing that on the SPID.