The truck pumps are harder to find. There are places that can rebuild them.
For most trucks, the car pump and pulley assembly is a direct interchange and car pumps are plentiful.
Regarding NOS, you have to be careful with that. Something that has been sitting on a shelf for years can be in worse shape than something that has been in use for many years. Simply the age of the part, and also how it was stored play into that. So in that regard, it may be better that you ended up with a remanufactured pump.
Lawrenceville, GA