Truck Identification (Original Options)

[JRB]

I know about the sticker on the glovebox door. What I am trying to figure out is what was the original motor in this truck. I have some numbers I will post below.
Model# CS10934
VIN# CS149Z861917
W/Base# 127
The only other thing in the options on the sticker that might give a clue is it had a Heavy Duty Clutch as original equipment. That is the only mechanical thing besides the gauges on the sticker. If anybody has a clue as to what the numbers above mean or where I can go to decode them please let me know.
After doing some footwork I have found that the Model Number shows that the truck should be a 1967 Longbed Fleetside and its a 69 Shortbed Stepside. I am begining to believe the glovebox was changed at some point in time and the sticker wasnt.
Thanks,

JRB