Hey D.Todd!

I too have my own numbering system that I've been using for almost 10yrs... (WOW does time fly...). It too is very simple, it uses two (or three) characters to denote the state or country of origin (NV = Nevada; CO = Colorado; MF = Manuf; MLD = Mold; etc), followed by five digits (Hex digits or base 16) or 65536 different chips per region. I also use either ‘3’, ‘O’, ‘R’, ‘X’ to denote if it is:
3 = 360 dpi scans of the obverse
O = 100 dpi scan of the obverse
R = 100 dpi scan of the reverse
X = 360 dpi scan of the reverse.

Thus a chip from Colorado that I've scanned at 360 dpi (with both sides being the same would be CO0031F3 (for the 799th chip in my Colorado Collection), while one with a different obverse and reverse would be CO00336X for the reverse scan of the 822nd chip in my Colorado Collection...

For the 4854th Nevada chip in my collection (which has the same design on both sides), the number given to it (and also the 100dpi image) is NV012F6.
And so on, and so on, and ...

Thus I use a numbering system that is also the name of the scanned image...

There are numerous numbering systems that are in use, some with encoded meanings, some just a quasi-random number - all have they benefits, and their deficiencies...

Regards,

Dick