If you call your nearest Hobart Parts place they can tell you. If they refuse this simple request, log on to www.hobartservice.com
and look in the discontinued products menu, select Food Machines then Mixers and sift through the files until you find the documentation for serial numbers/dates. The lists are not complete and stop in the late 1980's. If you're lucky, you can find out which plant manufactured it, as the first two digits of the serial number indicate where it was built. The serial numbers are not in code, so it's relatively easy to get a date if you do the math. While you're there, download the manuals for parts and operation. You won't find the service manuals..."Top Secret"! Good Luck! Ricardok45.