It is an early Kenmore, and they are very good machines. I know it dates prior to the 1980's because that's when I bought my first one (the model number on mine starts with 158.xxxx.) This one will have a model number less than that---maybe in the 140's ? I agree that the door at the top is probably for inserting cams to make stitches other than a straight stitch. The Kenmores in the 158. series have the knobs for fancy stitches right on the front of the machine. If you post your question on the "antique/vintage machines" forum, I'm sure you'll find experts who know much more about this machine. I say definitely go and see/ try it!