nice piece Keith. It's not doing it for me as an official pub or tavern measure - and though such things weren't always marked, the fact that it's copying a full sized wide-lipped bottle - possibly a Prussian from c. 1810 - 1840 - makes me think more of a single serving table bottle. There are a few examples of measures showing in McConnell's book, and like others of their ilk they appear quite different to yours, though it has to be said that measure marks can sometimes be difficult to find. There was a member here some year or two back who collected measures and had a v.g. collection - located in Canada I think, but not seen him for a while - he would be more likely to know if this was a measure.
The lack of decoration and the untreated pontil scar suggest a more utilitarian piece, and the absence of stopper wear would suggest this isn't simply a miniature decanter.
Bottles of this size and intended as carafes were mostly without lips such as yours, and with unadorned necks. Is that lower ring either deformed or damaged?
So - I'll plump for a table serving bottle rather than a measure. Regarding the bloom, you might try some Magic Balls (copper covered steel balls) - place in bottle with a little water and shake vigorously - not you, just the bottle

P.S. am sure there must still be pix on the Board somewhere showing some of the later Victorian pieces that were genuine measures.