To answer your question about the switch I had to look at it when I got home. I forgot that the red ’58 Elgin control has a toggle switch for ON/OFF as well as the buttons for Start and Choke. Before I got that control I used a set of West Bend ones that just had the Start and Choke buttons without the toggle switch – like the ones you have.
Since you got me interested, a look at a 1957 Elgin Accessory Catalog I have shows they made a third model for the smaller 5 1/2 and 7 1/2 motors that didn’t have any electrics/buttons. I’ve never seen one of these in the pink, below is a quick photo of the illustration – the ends do look very similar to OMC ones. However, as you can see on the lower left, there is an involved multi-part "kit" that mounts on the motor to allow you to use the controls – it’s certainly not simple like a Johnson or Evinrude!
