The Mortise Lock Assembly Dropped Into Channel Of Door - Can You Identify?

Hey Roy. The handle set looks like our 82-089; so long as the thumb lever was closer to one end of the pull than the other, this should work correctly. Without seeing the original mortise lock, it's a bit difficult to say what you need, as this handle set type works with a few different kinds. I suspect you need the 82-218. The hole looks right; also, there are many stories of this lock falling into the door frame when people try to remove and replace it. Just make sure the mounting holes on the door match what is shown below, as well as the general dimensions. The video below shows how to install this mortise lock. Check it out.

Profile view of 82-218

Opposite side view 82-218