Hi Kevin,
I think it is a generic label. And the letters may or may not mean something...
I had the label on a Scandinavian vase
>> LinkFrank even suspected (last post of the linked thread) that the label was Chinese.
If you search the board for "rooster label" you will see quite a few different pieces.
I seem to remember that in one of Heiremans Murano glass books, there are two of these labels found on high end pieces (from different makers). Sorry, I had the book from the library, so cannot check.
Michael