Submariner Bracelet Number

[kepler22]

I suspect there have been lots of threads on this topic, but I cannot find one relating to this issue. I have a 16610 and looking at it through a loupe I can see the bracelet no. 93250, which is easily seen. However I looked further and on the polished piece of the bracelet there is what looks like a handwritten number next to the hinge, 918384. Does anyone know the relevance or seen a similar number. I would post pics but its too small and faint. Apologies mods if this has been raised before.

[Tools]

Asking what a "handwritten number" means may create a pretty far leap since we cannot get into the mind of whoever scribed it.

If I had to guess I would say that it matched a serial number and was scratched there during a service so it could be mated back up with the proper case.