David â€” The 1939 Royal Brierley Crystal retail catalogue states on every page
See the safeguard of quality marked on every piece . . . the name 'Royal Brierley'.
I expect they all said more or less the same thing in their PR.
In the real world, you get a big order in from a trade buyer who doesn't like their glass marked, then you "forget" to mark it. You don't want their next order going down the road to one of your competitors.
In the same way, "quality" varied according to the buyer. Royal Brierley pontil mark finishes were of three types, rough, ground out, and de-luxe feature finishes. I think it's fairly obvious which type would have gone to Liberty's and which would have gone to Joe Smith's Emporium and General Stores in some small unknown town.
The most important book I ever had through my hands was a late C19 Hobson's Fox-Hunting Atlas. These were made up to order, and this example had been ordered by an unknown Derbyshire farmer. The Derbyshire map and those of the adjoining counties were OK, but the rest of the atlas was made up with rejects and out-of-date maps. The Cornwall map had been overprinted with the Devon hunt boundaries! Well, it was a map historian's dream find. That one junk atlas sorted out virtually the complete history of the atlas, much of which was previously unknown. Hobson's atlases previously owned by Lord this or Earl that told us nothing.
Anyway the point I was making is that PR and reality often don't have much in common, not just in glass but across the whole retail sector.