What model truck do I have???

[wannabeburbowner]

This might seem like a simple questions to you more experienced guys. I am new to the truck scene, and just bought a 71 chevy LWB. I don't know what the model is, I am not sure how to tell. There are no emblems on it, no door panels, just a plain black seat. What are the "clues" to tell me what it is?? On the title it says that the model is GS1, what does this mean?? The VIN is CS1411615200. So this means that it was originally a six cylinder with a TH350 right?? Is there any way to see what gear ratio I have too, without taking off the cover?? Also, my uncle gave more some door panels. They are black with woodgrain on them. They are not completey flat, seem to be molded plastic. What did these come out of?? I need armrests for those door panels if anybody has some. Any help is greatly appreciated.

Thanks,

Travis