It is getting harder for those inexperienced with Murano glass. The Chinese makers are pinishing paperweights, perfumes and some types of vases to a good standar these days. The easy spot of a ground base has disappeared in many cases.
I think the Murano makers have themselves to blame due to their refusal to mark properly their product. A furtherhassle is that they rarely follow a design like Czech or Scandinavian makers do. Thus the Chinese makers got away with sloppy work because of Murano makers being so keen to be freeform and unique.
I find a huge number of Murano items from the 50s and 60s era are not Murano at all, they are Japanese, by brands like Iwatsu, Kamei, Sanyu, and Hineri. I remember when they were new the simplest way to diffeerentiate was to look at the small included bubbles. The Japanese had almost none compared to Murano glass of similar types.
I live in Australia and high end Murano tends to be unusual here. so I make no claim to really know Murano makers as I have not seen enough labelled or signed work. I think one can still notice the Chinese makers lack of style - they tend to try to include far too many methods in one item, they tend to make things massive, and they use large amounts of coloured glass that Murano makers avoided by using reflections to make it appear they used lots of colour. That style of Chinese perfume is similar to these vases that come in many colours - but the finish of the base etc. is now well done..