Sorry I missed this before, but the Jollyboy was indeed a special shape of the City de Luxe pipe. It was introduced at the end of 1922 or the start of 1923, and the sales pitch was this:
"If you are inclined to be a "wet smoker," and many smokers are, you will welcome the introduction of the "Jollyboy" illustrated below.
This pipe has been especially designed by the makers of the well-known GBD pipes, to prevent the nicotine-laden moisture in the stem of the pipe reaching the mouth of the smoker. This advantage, obtained by a specially constructed bowl and stem, does not depend on any patent cartridge or filter, and combines the best features of a Bent and a Straight Pipe. It is light for its size, does not drag on the teeth, and as the bowl is well below eye level it is particularly suitable for Golfers and Billiard Players."
Like the other shapes within the City de Luxe catalog, it sold for 5/6. The reg. number, which reflects the design, was there from the beginning.