First off, make SURE the gearing of the replacement motor mates with the truck gears properly and runs freely without binding or slop. If the motor works with the truck, there's no reason not to swap them. You might slip the other motor into the other truck and see if it had a problem, that might indicate a latent issue with the swap you're considering.
The PS/3 had LED drive for the lighting, so your CV board would have to keep the lights on all the time from track power, you won't be able to control them from the remote. If that's not an issue, you can keep the CV board.
