A friend of mine has made a tool for removing the pins, and we've tried.. A thin tube with an internal movable solid steel wire pushing the pin down.
With a certain force (pretty large, frankly) the pin jumped off when pushed down, with a "click". Out of my curiosity I pushed it back into the connector to see whether its removal has deformed the teflon - and it clicked nicely when I pushed it in and also when I removed it back afterwards.
No idea what is the part number or the type of the connector, I got a bag of them decades back on a local flea market almost free, the half of the connectors with pins inserted in (somebody played with them and they stuck).
So be careful when inserting the pins into the BNC connectors, it might be pretty difficult to get them back.