Craftsman Block Grinder

I picked one up today and it seems to be in excellent shape. It also has what seem to be the original grinding wheels. I was a bit bummed to see it is assembled in Mexico and has a plastic housing but i bought it ninetheless. its an improvement over my current one. I'm not sure how old it is. It does have a 257 prefix for the model number so it is a true block grinder. I picked it up for $45...not a steal but I felt a good price. Anyone know how old it is or how to decipher the age from Catherine serial number? Did I do alrit? My only other bench grinder is a craftsman that is about 8 or so years old and it just seems way low on power and always bogs down.

Nice find, I've seen a few of those online but not in person yet. On the older ones the date is stamped on the metal plate on the bottom in ink. Not sure if that will have that plate or not.

The ZIP code for Sears is from downtown Chicago around the Sears tower. That means Early 70s through early 90s.

Good call on the zip code. It was before Hoffman estates. Does anyone else own this same grinder? It seems to run really well. Is this as good functionally as other paramount made block grinders?