A "reproduction" is a new bottle made as a replica of an old bottle. There are many collectible reproductions of the original E.G. Booz bottle, for example.
A fantasy bottle does not replicate an old bottle, but represents a designer's conception of a "cool, old bottle." A fantasy bottle is a new bottle made with an old-style or ornate appearance.
Fantasy bottles are not antique bottles, so there is no established market for them. They are worth whatever they may bring at the flea-market.
We have no FAQ list on this forum; however, you can search this forum for references to the terms you don't understand.
The original GI-37 was made at the Dyottville Glass Works. This was one of the only historical flasks to be produced without a pontil scar. McKearin says: "...the only flasks recorded with 'smooth' bases are flasks in designs first produced in 1847/48 Dyottville-type Washington-Taylors...."
Having reported that, the base on this flask-in-question does not match any type that McKearin figures. It looks "not of the period" to me.
Yes, I suspected that it was, but sometimes you just can't tell by looking at a picture posted on the internet.
The neck and the pontil scar just didn't look right, to me.[sm=rolleyes.gif]