Need help understanding what was done to my '63 Valiant convertible

I couldn't get the tape measure right up against it because of the center cap on the wheels, but from my eye it looked like 4.5" x 5. Rear end has the same bolt pattern. Though it does still have the 7 1/4" rear end. Didn't think that was possible. I'll take the center caps off tomorrow and confirm.
Some later 7 1/4 rears had the 4.5 inch bolt pattern - I think. May be wrong about that. Are you sure it's not an 8 1/4 rear?