I would not jump to any conclusions because of the finish of the pontil mark. There are oodles of glass makers which habitually finished their products the same way as WF did. It only underlines that a piece was made in a production facility with a pontil grinder, and that the top was finished (or else there was no need for the pontil operation).
Completely flat on the base - meaning ground and polished, or mould blown with a cut top? Either way - Aseda have made vases in all three finishes: completely ground and polished bottom, mould blown flat finish and ground out pontil, sometimes combined with flat polished bottom. Sea favoured mould blown finish, avoiding the additional operation. Johansfors and Gullaskruf often used the combined flat polished bottom with ground out pontil mark. WMF used either moulded finish or ground out pontil mark. But there are other makers for baluster shaped vases in clear cased smoke grey...