For sale is a vintage Centralab rotary switch model SA-301. Looking at the movable contact, it appears to be a make-before-break movement due to the wide paddle on the rotor (see 4th picture which is of the back of the switch and you can see this).
I have 6 available, and if you want more than one ... feel free to make me an offer.
Box also has " SA2016-4B" stickered on one end (see last pic). I assume this was some sort of internal part number for a company long before I acquired them.