@dcon - That is pretty much what I've come up with so far. It definitely looks like a Dublin.On the other hand... if they were transitioning to the new 4 digits (which, I think was a year later). It could mean 4 (group size), 1 (bit- tapered), 5 (general pipe shape - Dublin). It does resemble a Dublin a bit more than a traditional billiard, not quite as canted as many Dunhill Dublins.