The same motors are not commercially available that I know of. They may have new motors that retro-fit, but they are nothing like the in-house motors Lux made in Connecticut for the G. However, always OE motors on eBay if you can test armatures, oil/replace bearings and replace brushes. Just stay away from old motors coming from high humidity areas/basements if you can.
I just bought a beautiful, rewound armature for a Super J....can't wait to try it. Brushes were like $12ea...eeek!
Love me the turquoise G's....couldn't have enough of them! Great find on the tan/bronze G's BTW....
Kevin