Did Vereinigte Silberwarenfabriken only make solid silver, or silver-plate, too?

[AllSeasons]

I read on this website that Vereinigte Silberwarenfabriken was formed from a merger of Gebrüder Glaser and Wolf & Knell, and was active from 1914 to 1929. However, their mark does not contain the crescent moon and crown, even though they started quite a bit after 1886. My question is did they make strictly solid silver, or did they make silver-plate, too? I saw the marks below recently on an item, but could not be sure if it's solid silver or not, based on the marks. Any insight would be appreciated.

The image is below. Thank you in advance!