Hello,
please call me if you have questions or if I can be of further help. This is an old slider with a latch that needs to be replaced.
Thank you,
Bill
Dave Sr. from SWISCO responded:
October 11, 2017
Take a look at the 82-037 lock assembly. I believe this could be the part you need. Just be sure that it does match up to yours. The related thumb turn is the 82-043, if you need that too.