Ekimp - sorry, really not sure about dating of moulded neck rings - there seems little in the books to help - though it would be easy to say that it came about more or less the same time that industrial methods gave massive boost to press-moulding c. 1840 ish., but I don't think that would be true - always possible that moulding for neck rings presented some difficulties in the early C19.
There are moulded bottles from v. early C19, but captions seem quiet on the subject of whether the rings were applied or moulded, and not easy to see just from pix in books. I think there were many instances of prefigured blanks that were pressed but still had rings applied. At a guess, which isn't a v.g. way of doing things, I'd suggest c. 1830 - 1850/
yes, agree that taster pegs probably collectible on their own - picture attached of my one and only, as must have parted with the others. this one is about 5.5 inches long (c. 14 cms.) and has the cavity at the opposite end to the one here - in view of size think it might have been designed with something special in mind. Think you might get p ... on two or three of these and always an idea that you might walk around with this in your pocket when visiting friends and sampling their booze discreetly.
You have some nice glass LEGSY - very envious here. Don't think I've ever read anything about four neck rings, but often forget what I have read.