To the best of my knowledge, NEGC did not make personalized weights. These weights are usually considerably larger than the typical 3" NEGC poinsettia. The dates are all 20th century dates. And people have researched the names on them and they are usually people who can be identified with some effort. Several authors have identified the actual makers of most by analyzing the style of the lettering, including the grandson of one of the makers. They are not to be thrown away. They used to be available at auctions and estate sales for less than $50 each, but such a price would be a bargain today. It is especially nice if you can find several related paperweights for members of a family or a husband and wife.
At the very first American Antiques Roadshow, Alan Kaplan put a value $1,000 on a paperweight with flags and a date and bearing the name of the Mayor of Somerville. That single episode caused a lot of collectors (including me) to take a second look at these paperweights and start collecting them. At least two collectors have over 100 Union weights in their collections.
You can sometimes find them without a date and name, but they still are crude compared to the skill of NEGC.