I also have the little "B" on my orange-mustard non-denomination Tango. It's not on my red 50 Tango or the blue 100 Tango.

Probably same story with this "box" 100 crest and seal chip. This one (or ones like it) were used at the Balinese Room, Galveston, Texas. This chip may have been from there and then later stamped with the little shamrock hot-stamp. This was done to a number of them:

Robert