Patio door thumb latch

I need to replace two of our thumb latches. The "thumb" part is extremely loose on one door and loose and no longer latches on the other. The part # 82-049 looks identical but I am measuring 3 1/8" top to bottom and 2 1/2" screw to screw. (A little smaller than the shown measurement) I don't know when ours were installed but close to the 1986 cut of listed. Not certain what to do? Thanks