Welcome, Steve. What you need to find out is just how the '52 is titled, engine number or serial number. many states used the engine number prior to '55, so it could very well be titled that way. If it is of the serial number, you could pop the spot wels holding it to the original cab, then simply spot weld it to the new cab. I beleive the number might be stamped on the frame as well, somewhere on the top of the left side frame rail near the steering box. Don't quote me on that, though. I know that it is on the '55-'59 trucks, not 100% sure on the earlier trucks.
Again, check with the local DMV to be certain on what the laws are for your state.
