If I were in your shoes, I'd get a machine shop to set up for
cutting one gear, then get three or four more done at the same time.
The initial cost for setting up a cutter is the highest.  Subsequent
copies can then be sold to recoup the cost of the entire order.

I know that gear, and it can wear quickly.  The Seeburg piano that
used it was located at the New York State fairgrounds and it went
through a couple of them over the years.

Best!
Bob Hodge