Polly, I have two Necchi machines. Both are the BU models, one industrial on a power table and the other is a portable. I had the industrial one gone through and the other is in need of work. One of my future projects.
There is a Yahoo group that is dedicated to the Necchi machines, NecchiSewingMachineClub and they are dedicated to the older machines. They are also a fairly active and friendly group. I did look in their files and according to the model number your machine was built in Taiwan sometime between 1982 and 1988.
From what I can gather most Necchi models are great machines. The older ones built in Italy are highly prized and called the Ferrari of the sewing machine world. They should run super quiet because of their precision made gears. I have looked at stuff about their history and it is pretty cool as well.