hi - welcome to the GMB Nick
You could well be correct with your suggested date for this piece - like most things dating isn't quite the exact science we might wish for.
My thoughts for what they're worth .................. your elongated (ovoid) bowl is more typical of late C18 shapes than C19, and IMHO I'd suggest this one has a Continental origin, not British. This is based mainly on the octagonal collar under the bowl, the gilding and the overall shape of the stem and foot. The slightly tall ovoid bowl was the first of the bowl shapes for rummers - it was longer and less squat than virtually all of the rummer bowls that came afterwards - possibly it was taken from the bowl design of the goblet - although in general goblets didn't have these chunky square moulded feet. So my suggestion is a rummer rather than goblet, but if this is Continental then maybe they might have termed it a goblet.
We all get accustomed to looking at glass from our own country, we forget that not all countries had the exact same styles during the same time frame - similar but different.
British rummers don't occur befor c. 1780 - and within a very few years the bowl shape settles down to what we mostly recognize as the typical shorter ovoid bowl - and as you say, the glass becomes thicker and more coarse as time goes by, so thinness (in rummers at least) generally tends to indicate an earler piece. Gilding on British rummers is very uncommon, and the gilded rim on yours is possibly more typical of Bohemian/German pieces - but that's really only my opinion. How is the rim finished - fire polished or cut/bevelled and polished?
Can't imagine in a million years you will locate a makers name, or even the exact country of origin - but who knows, perhaps someone here will come up trumps - fingers crossed
Ref. 'Rummers - A Social History Told In Glass' - Timothy Mills - 2013 ......... very good book and well worth the money, although concerns itself with British material only.