The door latch in the photos has a small spring inside that has broken. It is from my Kolbe an Kolbe sliding patio door, which was installed in 1992. It appears I can reuse the brass setback plate that fits in the mortise by unscrewing and replacing the latch mechanism.
Tom from SWISCO responded:
July 6, 2017
Thanks for choosing SWISCO. Looks like your mortise lock matches our 82-229. Can you check the dimensions on the item webpage? Compare our part to yours to see if it will fit.