I agree, but it does appear that's what was they were thinking.
I doubt they used some sort of self tapping screws but who knows.
We may have some folks here with AC experience and I hope they come into the discussion and tell us what we don't know.
I understand the reluctance on tapping holes if it is something you haven't done much. If you have a way of measuring the hole size I can give you an idea of what size tap you would need, and maybe they missed the holes when building the motor. You could then compare it with the size bolts you have in the old setup.
I would likely start tearing the old setup apart and see what you have. I'm assuming the motor is shot anyway and it has to come off.