I am sure you are correct - your weight has a spurious date that is 'commemorative' of something. The canes are 1950s-1960s style. I have seen images of some Murano weights from the 1930s, and the canes are simpler than the ones in your weight, and are large, and set on a spatter base. I think the concave polished bases are a sign of weights from 1930 to 1950 or thereabouts - the flat polished bases came later.
I do not know of any hard evidence for the design of Murano weights in the period 1845 - 1930 (or even of their existence) other than the Bigaglia weights from the 1845 -1850 period. There are various scramble designs, some of which may be late 1800s, but that is speculation - I believe some of them are actually pre 1845. If anyone has good evidence of the use of - and style of - millefiori canes from Murano in the 1850 - 1930 period that would be a real advance in making firm attributions.