I'll stick with the early 1900s wind-up phono platter. None of the field wire spool ends were cast iron (which this appears to be), all seemed to have a larger center hole than the found one, and all had at least one extra hole toward the outer edge that the wire ran through.
Telling us what country you found it in would help.
Check the link on my first post above.
Yes. I think you are correct......