Hello Judy,
It's a 128. The way to tell the difference between a 128 and a 28 is to see if there is a thumb tab below the tension discs. Only the 28 has the thumb tab.
So far as I can see on the photo, the serial number starts with JC, which gives the year 1948.
Last edited by Muv; 05-14-2013 at 12:24 PM.