72 rearview mirror placement

[Mad Dog]

Everything I have read has told me that in 1972 chevy started putting the rearview mirror on the windshield.....
But my 72 mounts on the roof, like the earlier models. A friend of mine also has a 72 that mounts to the roof.....

What gives? Did someone retro fit an earlier mirror mount on both of these trucks? Or is this just one of the many times that the factory just used the left over parts that they had from the previous year?


I know that it's not really important...but I'm curious.