Pauly's archive did include items that predated the company's existence, though - the 2005 Sotheby's sale, The Pauly Collection of Murano Glass, illustrates a few items from the latter half of the 19th Century. Presumably, then, they bought up older stocks from factories as well as retailing contemporary lines.
That means, unfortunately, that the date of the company's formation can't necessarily be used as a baseline date for items bearing their labels.
Although, yes, the label itself is much much more recent.