[Andy Saunders]

Small data plates like this certainly appeared in profusion across, for example, Me 109, Me 110 airframes etc. Often, but not always, they were stamped with the airframe Werke Nummer. However, they should not alone be considered as proof of the actual airframe identity as these plates were clearly mixed and matched. I know of several Battle of Britain Me 109's wrecks where the "wrong" W.Nr has turned up on such tags. Equally, I know several wrecks where multiples of these plates have been found - all bearing the correct W.Nr for that airframe. Certainly, they should not to be considered to be the main data/constructors plate which was a much larger beast. On the 109 this was generally fixed port front side of fuselage, above wing root area. You are correct that 8 = airframe type, 9 = engine or an ancillary part thereof.