Bell System Public Telephone Flange Sign Marked "23"

[magicbrain]

I don't know if this has been seen or documented before - this Bell System 11" X 11" sign is marked with a "23" in white on the flange - I decided to bid on this sign due to the very good condition & high enamel shelving - also I don't already have one.

[Sargeguy]

 Yes, the small round ones are 21 and 22, this one is 23  in the larger one is 24. I think the booth sign is 25 or 26.   All of the small round ones are marked, but most flanges of this type are not marked. I am not sure if the difference is due to different manufacturers' practices.