Hello Patti,
Not a great deal to add, other than to agree with Frank's observation that the FBS mark is almost certainly a retailer's mark. It is certainly seen on a variety of French glass, I had a smoke coloured glass vase with this mark some time ago. It had acid cut decoration and was most likely to have been made by Daum, though I couldn't say with absolute certainty.
On my vase the mark was an acid stamp with the divided circle similar to that shown on the Monart vase on Frank's site, however, mine differed in that there was a second, outer circle, containing the words 'TRADE MARK'.
Interestingly another example of your vase has turned up for sale, see here:
http://www.stylefrenchantiques.com/pages/accessories.html The seller has attributed it to Muller Freres, though I woud question this attribution as firstly the vase is unsigned and secondly the vase appears to have a coloured casing over a white core while the (admittedly few) Muller Freres mould blown opaline vases which I have handled have always been in solid uncased colours.