If you look at my machine below, the arm comes to rest on the green stop. Does yours, or is there a gap? If so, what happens if you try and lift the operating arm up highlighted in yellow? Does it move?
Yes, your mechanism is from a later machine, probably either a Nevada or Sheerline type. It has a nylon bush on the operating arm lever and nylon star wheels on the reels. I guess swapped in the past.