As long as they are both hand reverse units, the same motor is used in both. The hand reverse mounts to the frame of the 253, and the motor on the 252. It will just move over.
The 253E motor with the 2-position e-unit is wider due to the e-unit. You'd have to remove the e-unit or modify the 252 frame. I get $20-30 and sometimes more for the reverse units on eBay. So if you bought a 253E you could remove the reverse unit and sell it on eBay.