Well, first I better confess that I am not an expert. When I saw the labels, I became increasingly unsure if Seguso and Barbini were good guesses. I know they are generic Murano labels. I haven't seen the red label with the Murano in script for Seguso before. I usually associate this type of label with the generic Murano. Seguso often used a red label with block letters. Has anyone seen Seguso with the script label before? (I saw what looked like a F'lli Toso paperweight that had the script label, so it could be that any company may have pieces that have this type of label -- I don't know.)
The spot bowl reminded me of Barbini's spot bowls. It has the two-layer white dots that have the layers offset. Of course, being similar doesn't necessarily mean it was done by the same people.
David, the yellow "Made in Italy" label looks like the one on the Bianconi-like fazzoletto on eBay the other day that we decided looked like Fratelli Toso. I have a feeling that it is not overly useful for identifying the company, though it may help put a date on the bowl.