Hallo Meld en welkom,
Yes your bowls are made by VSL, listed in the 1908 catalogue as 'Rince-Bouche' or a bowl to rinse your mouth at the dinner table.
I've always wondered though, if you're having dinner and decide to do this with the contents of the bowl, water i presume ...then what? Imagine yourself being invited and ending up with your mouth full of water

... I guess we all know what question's coming next

I can see them being used as finger bowls too and it's perfectly normal that they're not signed, I would actually have doubts if they were signed because that would mean somebody added a signature.
Below the image of the 1908 catalogue.