Inspection of a 904 torqueflite

On the 904......from the front of the drum. It steps up
On the 999.....it steps down. It not being burned has me thinking it’s original but I go back and forth.

If .050 wore that thing down.
It wouldn’t be smooth if the reverse band wore it down. It would be grooved and have hot spots if it was naturally worn down that much.

The converter is going to be rebuilt by a company up the road.
The 999 drums are beefed up in the rear planetary drive lug area.
The step area has nothing to do with the rear band. It is to leave more meat in the drive lug area where the rear planetary engages.
You are mistaking this step as drum wear, it is not.