This model is special as the name "JEC" was used for multiple stage models. There is a "JEC" equivalent for each DEM model since DEM-3000K. They can be identified by the seventh number of their serial. 

"DevKits of model number DEM-3000JEC differ in generation according to the seventh digit of their seven-digit serial number. DEM-3000JEC DevKits with 7 as the serial number's seventh digit are of the same generation as DEM-3000K, and those with 8 as the serial number's seventh digit are of the same generation as DEM-3000L."