Pontils with dimples? With letters and numbers?

[butchndad]

I’ve found 3 broken bottles at one site which are almost identical in size shape and color. They all have a bump or dimple at the center of the bottom. Reading past posts there seems to be some differences of opinion as to whether they are pontils or not. Is there a consensus? One of them has a “B” on one side of the depression and “10” on the other. Another bottle also has the “B” and something I distinct on the other. The third bottle has no markings. What is the significance?

 

[CanadianBottles]

I don't see any indication of a pontil on these ones. They look like the bases I see on late 19th century British beers.

 

[Harry Pristis]

The bump or "mammilon" is NOT a pontil scar. It is a cast of a mold vent.