I think I can see bits that look like what might be silver fuming!
To be honest, I don't think I'm familiar with "silver fuming" per se - I'd LOVE to know what it's like, I've got a real thing about silver and glass reactions!
However, the nearest to fuming I know of, is the effect found on Mdina and Isle of Wight SG, when the gob of molten glass which is being coloured with silver salts (chloride or nitrate) gets detached from the rod and some silver gas escapes from inside and deposits itself on the outside.
There are a couple of patches on this sculpture which look like what might be what I'd describe as "trails of comets", found on early Mdina and IoWSG.