Single arm operator

Hello I posted four pics. The first One is from a thread that someone else asked I have the same issue and my operator looks the same. From reviewing remarks I think the 39-014 will work in its place along with the gasket 39-564. The arm on my operator measures 13 1/2 " from center of gear to nylon bearing. Please let me know if there's something I'm missing or if there is a different operator that matches this one. The screw holes are 3" apart as in your diagram. The external part of the cover measures just above 4". Approx 4 1/8 minus a smitch whatever that is. Thank you.