Check the yoke end shake, lots of older 63's and 34's had the yoke screw swapped with the slide plate screw...yoke screw is fitted to the yoke. If the cylinder flops out when you open it, it's got a lot of use over the years or some idiot swapped out the screws. It can be refitted but it's a PITA to do it.
The last non lock, non MIM (forged hammer and trigger) versions have a different yoke retention set up. If you find one of those grab it.
