quote from Jenny Thompson............ "The Designs Act 1842 created thirteen classes of ornamental designs including all manufactured goods.."
Numerically progressing upward from No. 1 they are .........
1 - metal
2 - wood
3 - glass
4 - earthenware
5 - paper-hangings
6 - carpets
7 - printed shawls
8 - shawls (if not printed)
9 - printed yarns
10 and 11 - woven and printed fabrics of various types.
12 - woven fabrics not included in the above two classes
13 - lace etc.
for whatever reason - a fair sprinkling of glass items seem to have found their way into CLASS IV - either for devious reasons or simply that an agent working on behalf of an Applicant was unsure of how the system worked.
When research workers compile lists of items from CLASS III, they make the assumption they have them all since all glass Registrations are supposed to be in CLASS III - subsequently other folk then find an item missing for the very reason that occasionally they've been wrongly placed in CLASS IV.
Provided we have the Rd. No., and of course the corresponding date of the original Registration is known, then searching the Representations books at Kew (National Archives) will turn up the item in question - albeit showing CLASS IV, rather than III - but it will always be found in the Kew annals.
Unfortunately, some of the C20 published lists of glass Registrations - from reputable authors - omit these CLASS IV items, which makes for some confusion, since it's a failing of most of us to assume that published lists are infallible.
I've looked in the Blue Book (Glass Association publication), which continues where Thompson leaves off, which is the official list of Registrations from 1908 to 1945, but 767986 isn't shown. This probably means, as Christine has reminded us, that this is a mis-classed Rd. No. - it should have been placed in CLASS III, but is probably lurking in CLASS IV - another miscreant - but only time will tell.

P.S. the Continental 'sevens' may well indicate that this piece was made outside the U.K., but nonetheless Registered in this country. The world of pressed glass is littered with items that were manufactured in Bohemia, Germany, Czechoslovakia, France etc., but Registered in the U.K.
Very annoyingly this IS one area where positive attribution of a maker can still elude us - although Registered in the U.K., the Registrant/Applicant is almost always shown as being domiciled in this country, so sometimes we have to live with less than complete information.