The serial number is stamped in the frame of the machine on the bottom under the bobbin end. Most of the 301s were made in early 1950s. Mine is a 1951 also. Love that cabinet...the cabinets are not that easy to find. You can easily take the machine out of the cabinet to use as a table top...there is a latch on the bottom to release it. They have a plate on the bottom and feet (that can be replaced if yours are hard and cracked) so it can be portable. Mine didn't have a cabinet or a case when I got it.