I'd agree that it seems to have been an unusually small design variation to have qualified for a separate Reg. No............... maybe this particular incident was the first such design with more than one shape, and the factory were concerned to make sure they protected themselves against every eventuality - but I don't now have Baker & Crowe so only guessing. See the attached pix which do show clearly the differences between the two designs.
There is however, another matter that has caused some confusion - at least to me - by the fact that this pair of Reg. Nos. are absent from the Blue Book, and because I didn't check this point before visiting Kew - assuming without question they would be CLASS III - I didn't have it in mind to look in the Registers during my visit. So, I now don't know if these items were Registered as CLASS III, and the compiler of the Blue Book simply overlooked them, or whether their absence is due to being recorded in CLASS IV.......... in which case they were still overlooked.
Are there any known instances of Jobling Registrations being recorded under CLASS IV??
Whilst looking for these Celery designs, I noticed there were two other Registrations not too distant numerically - although I'm not sure what sort of animal/creature they're supposed to be - birds, fish, a recumbent fox

............ anyway I've taken some pix and can post if anyone wishes to see them - the object looks to be some form of ashtray perhaps? These are Reg. Nos. 795459/60, which date to 08.08.1934 - but here again there is a problem with the Blue Book insofar as only one of these - 795459 - is included.
Including those Registrations not in the Blue Book, 1934 seems to have been an active year for Jobling with what looks like a total of 26 separate Registrations, although in view of the errors then always possible this may not be an accurate figure, and as I say I no longer have the book, so can't double check.
Five pix in total, so one will flip over.