Difference between Blazer Tops?

[blazerboss]

I'm getting rid of my white hard top (1971). The guy before me cut a hole in the top for a vent cover (trying to make it a camper I guess). It's white if anyone wants it... solid other than the square hole on top (covered with a fiberglass sqaure).

My question is, is there a difference between the 1969-72 hard tops? I have my eye on one in good shape, but the guy doesn't know if it's off a 71 or 72. Visually it looks identical to mine, but on the ground vs on the truck are obviously very different?

Any pictures would be great.