is there any difference between 70 and 71 fenders besides the side marker lamp cutouts?

None that I am aware of. I do know for a fact that you can mount 71 fenders on a 70 and vice versa. I've seen it meself.

71-72 fenders have an inner pannel welded behind the headlight socket. if you are putting it on a 70 radiator support you will have to cut it off the fender. i have used 71-72 fenders on 70 but not the other way. the inner pannel that is not on the 70 fender might be needed on a 71-72.

great, thanks for the info