Can you post a photo? I don't know if I can help, because my set of Rider schematics only shows models R-35xx and R38xx. But if you'll tell me what tubes are used inside, I'll look and see if there are any chassis that contain them. I've found that several models used the same chassis back in those days.I have a 1939 Stewart Warner radio model 13-5U.
1939 Stewart Warner Model 13-5U
I'd love to see your radio. I think the cabinetry and styles of these old radios are wonderful.