Factory parts?

[RB72]

Hey my name is Ryan Burks and I'm 15 years old and love classic Chevys. I recently just bought my first truck to fix up which is a 1972 k10 Cheyenne. There are some parts on it that I'm not really sure if they are stock or add ons.... First I noticed how big the drive shaft is on a half ton.... Is it stock...?
Next the rally wheels.... I'm not sure if these are the wheels that came out of the factory or not.
Last the clearance lights.... They do not show up on the parts list in the glove compartment but they look too perfect to be done by somebody. If someone could help me with these questions that would be great. Thanks!