Gearmatic Winches have been manufactured since 1964.  Many of the original designs, like the Model 11 and the Model 34, are still operating in the field today.  Up until the early 1990's, Gearmatic winch did not steel stamp the serial number onto the winch.  Therefore, if you cannot find the data plate, you will be forced to take measurements of your winch, send in photographs and even count the number of teeth to properly identify the specific Gearmatic model you have.  

GearMatic Serial number

Gearmatic Winch Serial Number