Functionally, I think you're probably good.

The first M-Mount 35mm Lenses were actually the thread-mount versions, which Leitz threaded into the appropriate M-mount base (either with or without goggles depending on the camera they were intended to work with). My 35 Summicron has a paper thin spacer which makes a minute correction to the focus. If that were missing on your lens, then the focus indicator would be on the other side of 12 0-clock because the lens would thread in too far.

Getting the lens so that the focus indicator is perfectly vertical was a common problem with all thread-mount lenses, and they usually had some very simple provision to correct it. I'm guessing it's the same with this one.

Someone who is familiar with working on this lens could advise you better, you might try asking on FaceBooks Vintage Camera Repair Group if a local qualified Leica Tech. isn't near by.