Did you buy all three or only the Necchi? You got a bargain at that price. Necchi did not keep good records. Is your logo a VN or just an N? Is it a zigzag machine? Is it black or a pretty pink or liliac?
I paid $27 for mine at the Salvation Army store. Mine is pre 1950, black with no zigzag.
stitchnripper, FWs don't come ina domed cases. If it was 3/4 size with a bentwood case, it probably was a 128 or a 99 if that makes you feel any better.