Floor Pan Differences

Hello, everyone.

I was wondering if anybody could clarify the difference in floor pans between the original 60-62 Valiants and the later models?

I'm doing a restoration on a 62 Valiant, 2-door, but it seems the floor panels for these are as rare as hen's teeth. Many sites list pans for the 63 and up models, but I don't know if they can be made to work in the earlier bodies.

Thanks!