Kitchen exhaust fan lever knob

[Emittim3]

I have a 1978 Excella with the original kitchen exhaust fan/hood. Above the range is the sliding handle that once slid up, opens up the vent outside as well as turns on the fan motor. The knob on the handle is missing, so the remaining metal slider is almost like a blade to try and move upwards for open/on. Wondering where a source might be for a replacement knob for that handle?

Thanks much!

[Emittim3]

Here are pics of the arm that I'm needing to find the knob to.