I'd feel better if the source(s) was/were actually murano makers and not a retailer.
That being said, if weights are made in China by Chinese hands then the weights are indeed Chinese, not Italian (Murano).
To cite another example, it is well known now that in the 1920s-30s, American dealers sent 19th century French & American weights to China for the express purpose of the Chinese making inexpensive copies for the dealers to sell to collectors in America & Europe.
Many of these were well done and of course, are collectable in their own right.
However, some unscrupulous dealers tried to say that these weights were, in fact, the real thing, ie, authentic 19th century French & American weights.
Nowadays we know better and no one attempts to say that, because the designs are 'French' or 'American', or because American dealers encouraged their making, then these weights are 'French' or 'American' weights.
The weights are Chinese weights made by the hands of Chinese makers.
See what I mean?