Do "NOS" gears have lapping compound on them?
The yellow is not lapping compound, but gear paint for checking the pattern on the teeth. (maybe someone didn't like what they saw):dontknow:
It looks as though it had bearing race on the pinion, and the red stuff is a form of loctite that the factory uses.
I say someone bought it and changed thier mind for some reason.
If you get it take a look at the ends of the teeth on the pinion gear closest to the bearing side.
It's really easy to take a chip off of one of the teeth if you have to remove a bearing race after it's installed.
I would catagorize that as "installed but never run" but somebody doesn't know anything about it if they called that lapping compound.