Yeah. Its a classic. Sometimes new complete brake shoes has the wrong radius for a new brake drum. You can hammer on a couple of locations on the metal brake shoe holder to extend the metal and adjust the radius. Even though the tool that Autonovice used is far more sophisticated, this works pretty well.
However, if this was the cause of the rear brake shoe drag on this G. There should be visible difference in wear along those shoes shouldn't it?
One reason my guess is the brake hoses is that this G has been located in a very warm dry climate and most rubber parts (all?) seem to be shot on it.