Jim - Sorry for not replying sooner. I had to go out of town and just returned.
I agree with Karls summary of the major differences between the pickup and big truck body parts and 35-36-37 differences. There are also variations within each year, but that gets into rather fine and mostly unnoticeable details. If interested, let me know and I can share more.
What are you wanting to do: restore to original, looking for parts, etc.? Feel free to contact me directly:
Dave Gunnarson
[email protected]