[72 Cheyenne K20]

I wanted to ask if anyone has info on the different heat shields that were made for 67-72 truck models. I have 2 different shields that basically look the same in shape but have 2 differences. they both have the small hole on the right side of the face but one of the shields has 2 more holes on the face about the size of a silver dollar while the other is flat. Also the male fitting opening on top of the shield for the heat tube is slightly larger (1/8th ")and taller (1 ") on the shield that has the 2 larger holes. Both back pieces are the same and both fit the exhaust manifold. I have a 72 3/4 ton 4x4 that I'm in the process of taking apart and trying to make it as factory as I can. Any info on these shields would be great.

Thanks, Scott