I am looking for part# 126-720-0135 left door lock and need your help.

My 86 300SDL serial#276319 is in need of a left door lock with the above part#. I have found so far this # is no longer available by dealer, or Germany, it has been discontinued and is no longer made. This part # fits a number of models: 420SEL-560SEL-300SD-300SEL 300SDL with early serial numbers below A452296. My independent mechanic. tells me the new part number 126-720-1135 most likely will not fit due to the serial number break.

If you know of one or someone who has one of 126-720-0135 PLEASE let me know.

In addition I cannot find anyone who can tell me what is the difference between the two part# 126-720-0135 & 126-720-1135. Do you know?
Thank you,
Ron