The arm on the mechanism attached to "gear box" is 3 1/4 inches along the outside from the elbow bend to the end that connects to the link, which is flat and has the number 31850 stamped on it. The "gear box" did not want to come loose from the frame, and I did not want to break anything, so I was not able to get pictures of the mechanism out of the frame.
Emily from SWISCO responded:
May 23, 2022
Hello!
This looks like it could be an older version of our 39-315 operator but you'll want to compare our dimensions with your old hardware to confirm this matches up.