LEICA M-3

I had my 1955 M-3 serviced at LEITZ, ROCKLEIGH, N.J. in 1973. Why is there the number 92 where the L wax was prior to servicing?

Looks like that means it was serviced by Don Goldberg. See this webpage. .... Does that make sense?

Mine has a J, which means Gerry Smith, apparently, a technician from Toronto.

The 92 is applied by Don Goldberg and, apparently, his father before him. (Post 12 of this.) Beneath the wax is a screw. The place you brought the camera in 1973 may have sent it elsewhere to get serviced.

Does the camera still work properly? If so, kudos to whoever serviced it last, 50+ years ago, and to E. Leitz for designing and building a truly rugged camera.
But your question intrigued me, so I went and looked at my M3. Last serviced by (the late) Gerry Smith at Kindermann in Toronto in 2010, it has a wax seal with no markings. Never thought to look before.
I'd splashed the camera with salt water, making it unrepairable. Gerry told me "I could take the top plate, and put it on another camera, so you'd think you still had the same one..." We had a good laugh and I declined his offer.
Since then the M3 has been a display piece, as it 'looks' quite usable. It's a reminder of 32 years of use, thousands of pictures, and of my own mistakes.