Patio Sliding Door Hardware

I am trying to identify and replace the mortise lock that goes with this lockset. I can find no markings or engravings on the lockset. I'm willing to change out the complete lockset but the holes and recesses don't seem to conform to other lock sets. The mortise lock is not centered with the handle but rather offset because of the way the slide interacts with the keeper. The small black knob interacts with two lugs on the side of the mortise lock which moves a flat slide up and down to engage on the keeper. The mortise lock mounting screws are on 2-1/8" centers. I have more pictures but I could only upload 5.

This is on an aluminum sliding door, probably 1970's vintage. I can find no labels on the door either other than the name of where the extruded aluminum came from, Howmet Aluminum.