Those are some nice machines - enjoy them! I really like the library cabinet that the 101 is in.
On the topic of serial numbers, looking them up on ISMACS doesn't always give the right model. For example, the Featherweight here
http://bc.kijiji.ca/c-buy-and-sell-h...AdIdZ462849442 has a pretty clear serial number (EV902960), but ISMACS says that's a 196K. I have a Spartan (192K) at home with a similar mismatch. I assume this is a problem at the factory - someone puts a serial number from the wrong series on the machine - rather than a problem with the Singer/ISMACS data. It's rare, but it does seem to have happened occasionally.