Please read my post earlier in this thread.
The worm gears on Lionel's 700-series Hudsons like your 18058 are back-driveable. But it's a double-threaded worm, not a triple threaded one as used on the Berkshires. So the wheels will turn the motor only after a lot of break-in time. Lionel's 1990s-2000 Hudsons (the ones with a screw holding the wheel to the axle) are notoriously "tight," and will need a LOT of break-in time to smooth out.
Also twenty years is a long time and hardened grease is a real problem. Be prepared to dig it out and re-lubricate.
If I have to bet, your 1964 model may have enough track time that the wheels will turn when it arrives. But don't force them!
Regarding the handrails on the 18058, be gentle. If the connection breaks or it shorts to the shell, you'll have no wireless command signal. As MartyE said, the hinge side is round and the other side is straight. That plastic is insulation for the radio signal so don't remove it. Good luck!