I'm going to throw this at you.

When I did my '68 GTX, I got clip kits for the front and rear windows. The front kit was great....the moulding snapped on like a piece of cake.
Now...the back window.....


The clips were SO tight on the body that I was beginning to mark up the paint trying to install the mouldings. I ended up taking most of the clips off and slightly tweeking them so that there was a bit of a gap between the face of the clip and the body. After a couple of "tweeks", the mouldings finally snapped on like they should.

I can't remember where I purchased the clips from, but I know it was from one of the sponsors on this board.

Basically just saying that you'd better check the tightness before you commit yourself to basically having to POUND the chrome on.