A few bits of age-related wear on the base of something is only to be expected, worrying if not there, and not a problem (unless it drives you, personally, nuts).
The inner rim of the tops of these was not finished to a very high standard in the first place, it wasn't given arrises (tiny bevels on the edges)- it had to hold the bulb fixture and is often damaged with small nibbles because of folk removing and putting the fittings back on.
If you were to be putting fittings back on, they would most likely hide any damage.
I really don't think what you are describing is the sort of thing that actually needs
any restoration at all.
Unless you cannot live with it otherwise.