For John Deere steel-deck walk-behind mowers, stand behind the mower and locate the VIN on the left side of the mower deck.

Locate the VIN according to your specific John Deere tractor.In addition, each serial number is unique to a specific mower, and can be used to track and identify your machine. These 13 to 17 letters and numbers can provide important information about your tractor, such as the year it was made, where the engine was manufactured, its emission levels, its security code and its transmission designation. Your John Deere tractor vehicle identification number is also known as a product identification number, serial number or lawn mower identification number. Written by Sarah Mason Updated December 28, 2018

Probably for big equipment but I don't know. There's lots of info available for engine only #'s. This article has some info How to Read a John Deere VIN | Home Guides | SF Gate