Search Gottlieb Stepper on Ebay. There is a F style for $50. (Not mine) I don't believe that they are all created equal, so you might have to do some rewiring.
I also have a balls to play unit on there, but I don't think it will work for your purposes, since it was out of an Add-a-ball
ebay.com link: Gottlieb EM pinball machine match bonus unit small relay stepper assembly
I might have the part, but after my last experience of a hour at the post office, a $15 shipping bill etc. to send a ten cent switch, I decided that there were no more free parts going to Canada from me.
If I have the part you require, I could put it up on ebay for a buck or something with international shipping, then you and ebay could figure it out. Even at a buck, I'd lose money, because they charge you fees on shipping as well. Plus f'n paypal. Everybody bends you over.
Anyway, if you have any interest in that, let me know.