if Baccarat, then the back stamp should be circular, containing a wine glass, decanter and tumbler, although due to the wear you mention, might be feint and difficult to see, possibly, try using a lens. I'm unsure about the fire polished pontil though. If you rub the collar with your metal polish you should know instantly whether or not it's silver (but could be plated) - if silver then should be hallmarked - but assume no marks. Don't now what it might show if it is French.