This, in my opinion is an early one. I think Barry told me that in 1967, after some discussion he had with my father, for various reasons they changed the shape numbers to include the size of the shape and this 33 became a 333 X (at that time). In the catalogue, which I am looking at, and from around 1967 I think, This pipe came in a group 3 (size 3) only and was fitted with a saddle mouthpiece hence the X. In this brochure, there are certain shapes which were fitted with DC mouthpieces so the Catalogue is post November 1964. In the 1951 catalogue the Bell Dublin came in 2 sizes 33 & 32 which was a size smaller. These were fitted with a taper mouthpiece (similar to this one). I think that this one was made between 1961-64 . Please do not take my word on this, it is a gut feeling rather than factual.
I am learning each day and would be interested in other Charatan collectors' views.