It looks to be a 338. Here's a pic of my Singer 338.
If it is it will have all metal gears inside and only the motor belt. Nothing plastic to deteriorate and break. It does need the #1 ZZ cam in it to be used as a plain straight stitch / ZZ machine. Without it the ZZ feature will destroy needles and the SS is iffy as well. There are 30 some more cams you can get as it takes the flat cams.
I don't mean to make you feel bad about what ever the auction price is, but this one cost us $12.50.
Joe