I have seen berries like that before but the where and when escapes me at present.
If I had to venture a guess I'd lean towards a second from a US maker or a repolished antique French weight.
The flower just doesn't say Murano to me, and the knobly bits on the stem makes me think
the maker was dedicated to details, a dedication I don't see much of in Murano lampwork.
Murano lampwork, IMHO, tends to be coarser and not very carefully laid out.
I have a couple of modern California type weights and they both have completely flat bases,
so a flat base on a lampwork weight does not automatically mean Murano.
My guess on the base is that a problem occured that required someone to remove
a lot of the base. Or a previous owner thought the pontil mark was a manufacturing error and had it
ground and polished off.
It's a very nice weight