New York 50/70 rack / unit markings?

[JV Puleo]

I don't think there is any question those are unit markings of some sort. Most of the NY rifles seem to have some. The problem is that they do not seem to have been done according to a system - that each unit marked things as it saw fit and some didn't mark them at all. It might be possible to puzzle many of them out but it would require someone collecting data on hundreds, if not thousands of surviving rifles and carbines and comparing their markings to the known NY units. Oddly, I think it could be done because NY rifles have a very high survival rate, but it would be a great deal of work and would take years.