I'm guessing yours once was a hand crank. My 99K (1934) looks exactly like yours, but it has the smaller solid cast hand wheel. It was common to covert to electrical, and often expected that it would happen at some point. A 99 is nice enough to work on in general, I rewired mine and kept motor and lights. I'm still not sure I would use a hand crank much.
If you have the pedal and wiring looks intact enough, you could do some test sewing :- )