No bubbles that I can see and it was difficult to tell if the black specks are in the glass or inside the bottle, so I gave it a wash and they were mainly specks of dust. There does appear to be very minuscule bits when looked at with an eye glass, but not noticeable otherwise.
Those are both interesting suggestions. No sign of it having a top as such, Anne, so I imagine a cork stopper, but that could have had a decorative metal finial. If it were for religious water then a simple cork could have been sealed with wax, but certainly no signs of any fitting on the outside of the neck that would have come from a metal top as in Anne's example.
Ian