PRE 1960 (ASC172 - Pre 1960)
Early on, Cessna installed the lock below and off to the right of the handle, in which case our replacement lock has a cam that reaches over and up to lock the handle.
Pre 1980 (ASC172CDE)
Later on, they installed the lock directly below the handle which reaches straight up and locks the handle.
Post 1979 (ASC172CDL)
After 1980, Cessna installed the lock directly to the right of the handle and had a arm that reached over and put a pin the in the handle.
If you would like to confirm which version have, please submit a ticket with a picture of your door panel and we can advise.