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Hi.
There are a quite lot of Dupont paperweights around, some with various dates, some without - probably more of the latter. Dates vary - I believe it was possible to request specific dates, but I have no hard evidence for that. There are a good number of Baccarat pansies from the 1920s too - the odd one with a date, but these are quite uncommon.
In general, the Dupont millefiori versions have the canes set fairly low in the paperweight, and have less rounding to the lower part of the dome than classic period Baccarat paperweights, and often have a broad wear rim. The canes sometimes look as if the colour is 'bleeding' into the surrounding clear glass, and colours are often rather weak. That said, I think there are some Dupont paperweights around which include canes made in the mid 19th century along with later ones, which can confuses the collector a bit!
Alan