72 plastic door panel question

[MAK191]

so I went to a local wrecking yard and picked up a pair of what I think are 72 plastic door panels. The driver side is in pretty good shape, but the passenger side is cracked and metal trim is a little bent up. I can't find any GM markings on them. How can I tell if they are original and are they really for a 72? My truck had only small pieces attached around the arm rest so I have no way to compare. I only paid $15 so it's no loss I just hope they fit. I heard that some of the aftermarket ones don't fit so well. here is a picture of the driver's side.