Margi - I don't know if the same applies to Belgian or other Continetal made decanters, but as you probably know, good quality ones English ones do usually have matching nos. on both the stopper and top flange of the neck. This is one way of telling if the stopper matches or not, although sometimes these nos. are quite discreet - does yours have a no.?? I'm often knee deep in oldish decanters at some of the big boot sales, and the vast majority of these have bases that are worn/scratched fairly heavily. I wud be inclined to think that if there is little wear on the base of yours then it may not be quite as old as first thought. I don't have the book, but perhaps if you can get someone to look in the standard tome on decanters, it might help. However, at the end of the day, back to the old maxim - if you like it keep it. Paul S.