This article explains how to locate the model number on DEWALT batteries and chargers.
For chargers, the model number can be found on the top or at the bottom of the unit. If you look on top, it will be next to the charging cells where the battery slides in. At the bottom, you can find it near the warning label.
For batteries, you can find the model number at the bottom of the unit, printed or engraved directly on the plastic housing. It has an alphanumeric format and it usually starts with the letters DCB.