Hello My Friend!
Glad you took my advice and posted here as there just may be someone out there that has the Upper and Lower back doors for your slot machine!
Hopefully you can find them both in original factory made doors as they are very illusive!
Do you have the original Yale Jennings locks as those would be nice to have if you locate original back doors!
Email me if you find the doors as I can look thru my original locks and may be able to help you there!
I hope it is alright but I am posting the two photos you emailed me so others can see your slot machine!
Bona Fortuna!
MONTIORIGINAL KEY ABOVE with O.D. Jennings marking!