Hi - yes, I think that's a not unreasonable written interpretation of those last few glasses, though as mentioned I think there will always exist some pieces that will give rise to personal interpretation as to what is, or isn't, a merese or collar - plus, as you say Cagney, there is occasionally a different take depending on which side of the pond we might be standing.
However, aside from that and IMHO, I'd suggest we should exercise some care when describing some of these wines as being of 'five' or 'four' part construction, at least when discussing with European collectors - we're a very traditional and old fashioned group of collectors you know. You and I know what we mean, but I think European traditionalists will wish to maintain a terminology of 'two' or 'three' part construction - the conventional classification for the the main parts of a wine glass - rather than including collars and mereses as a way to increase the 'number of parts of a glass' to four or five even.

The drawn stem (the straw shank of the C18) glasses are always the two part wines, where the stem is drawn off - literally - from the glass of the bowl - to form the stem, with the foot formed separately. Collars and mereses do not occur on such glasses. Virtually all other glasses are three part - bowl, stem and foot - all formed separately and attached whilst plastic.
Of course States collectors may have been describing wines in this manner for a long time - but U.K. collectors tend to lag behind with such wording.
Thanks for the correction re the whale-oil lamp 'font' - what did you think of my suggestion of date for this particular piece? In the late C18 the construction of a superior oil lamp was invented by a Swiss guy - Aime Argand - which burned whale and seal oil and some vegetable oils and gave a far greater illumination than previous lamps. There seems to be little interest here in such lamps - Brits. were more into sticks perhaps - though I think States collectors have a far greater history in oil burning lamps re the whaling I guess.