Thought I'd once read that you'd be lucky to find a matching No. on something much earlier than 1890 - 1900 - but perhaps thinking has changed.
quote ……… "I’ve got a couple of decanters with numbered stoppers but they are definitely Victorian in style." The lady reigned for a long time - what sort of assumed date of manufacture are we talking here?
So many stoppers are replacements, or at least they are on bottles in the places I buy from - it's a surprise when one with a perfect fit is found - and sometimes the matching No. helps to confirm this.
Difficulties with dating bottles are the usual ones - caused by the many copies out there.