It's a featherweight, and it was made in 1951. You can tell the year from the badge on the front of the machine...it has a blue ring that was exclusive to the "Centenial" models...Singer's centenial was 1851-1951. I can't tell you anything about the case, but it's nice, and I wouldn't think matters much as long as the machine fits comfortably in it.
Looks like it's had some rewiring done (the white cord). Depending on what they want for it, I'd buy it.