Are there any mounting differences between a '70 fender and the '71-'72 other than the reflector?

No, they are mounted exactly the same.

They should mount the same. The blinker light and plus the front of the panel has an extra mount for the headlamps that the 70's didnt have/ need. So if you are doing some kind of conversion or using a different yr fender you may need to chop out that peice. I had to.