That should be an easy change. You would want a 481-1 truck, which would have a tab coupler and a roller, no sliding shoe. But when you get into this there may be additional work to do. I assumed this is a whistle tender. If so, the insulation on the wires from the trucks is probably hard and cracking. This should be changed to super flex wire. The trucks are held on with horseshoe washers. These may crack when they are removed. Make sure you have spares. The whistle may be in the way of removing the trucks, so the screws that hold the whistle in may have to be removed so the whistle can be moved aside to get to the horseshoe washers. While you are in there, you probably what to service the whistle motor. Check the motor brushes, clean the commutator including cleaning out the slots with a toothpick, and oiling the bearings.
The other thing you might run into is that the screws that hold the body on screw into plastic. Frequently the plastic is broken out around the screws. This can be built back up with JB Weld. Then redrill the screw holes and use a tap to rethread the holes. I think the stress applied by the self tapping screws is part of the cause of the plastic cracking, so threading these holes with a tap first helps reduce this stress.
The only special skill required to do this work is soldering. You need the right tools and materials to disconnect and resolder the wires. I am a big user of solder wick to remove the old solder. It makes removing the wires much easier.
