Volkswagen T-Roc engine number

I have recently bought a used VW T Roc from an approved VW dealer. The engine number (not Code) on the registration form begins with DADA, followed by numbers, but the number on a label on the side of the engine starts with DAD, then the same numbers as on the reg document. Should there be a difference? Also, is the engine number physically cut into the engine, if so, where is it located? Thanks!