The rims on that pair of vases are hot finished, grinding and polishing next to all that rigaree would be problematic I suspect.
There is a photo of the D'Humy blue:
https://www.britishmuseum.org/collection/image/390792001The vase has stripes in the foil but it is not obvious whether it has ribs (looks like not at first glance). They also have a close up photo of the rim and neck. Ribs are usually created by use of a dip mould or by being blown into a mould. A particular number is not much use for identification but could show consistency across a range of wares except when there is variation in size (more ribs would be needed to keep a consistent look as items get larger).
Ribs can also be made by picking up rods of glass on a blown bubble and then worked (maybe more of a Murano technique, thinking Seguso) very effective if you want ribs a different colour to the body of a vessel.
Mr Gulliver did have access to those pattern books, I remember asking him how he had identified a particular vase and it was from those books. How complete the books were? Not a clue.