Greetings from Downunder, Australia.
I have a 900g large paperweight which at first sight I thought was unmarked. On closer inspection I see a blob of glass which was dropped over the pontil and a letter "W" has been impressed into the glass when it was hot. Obviously, it could also be an "M" or "AA" or even "VV". There are many permutations, the only one coming to my mind is Adam Aaronson, but usually he signs in full, although I have seen an AA signature on a vase attributed to him, but this had a line through the middle to cross the A's.
Many thanks in anticipation of cluey paperweight detective lurking out there!
Barry