Hi Ross, In all my experience with Avondale, they only ever added a small. sticky. oblong. clear. with gold writing. label on their glass art work, except when an inscription was requested for a comissioned piece, and even then only an inscriptio not a signature.
Chris, Avondale are still a fully functioning company and you can contact them here:
http://www.vickybarrett.com/artandcraft/avondale/I am sure they would have a look at your paperweight and say if it is one of theirs.
I did say 'is it' typical of Mats Jonasson's work, not 'it is' typical, as, like Ross, I don't think it is his either. His signature varies considerably, but I find it very recognisable.
I don't know enough about American Studio glass to make a judgement there, but neverthless, whoever made it thought it was good enough to sign.
Rosie.
