Decent tub has correct vin number

I bought a 1946 cj2a. The body has some rust but is definately repairable, but that's always much easier said than done.

The frame is very solid and the jeep runs great. It came from a dry climate. I'm mulling the idea of buying a new body since I think the price is actually quite reasonable considering the cost of body work if you can't do it your self, plus the drool factor.

My dilema is this; the number stamped on the tub on the drivers side tub lip matches the title and the vin tag.

Would it be foolish to replace the body? Would it be illegal to remove the section with the matching number and have it welded onto the new tub?