Hi!
Disagree? No, not all...
All Me109's had the werk number stamped (or written by hand) onto the back of the Radio Access Hatch, the Luggage Hatch, the Windscreen framing, and other areas. I suspect this was incase of a loss where not much wreckage was identifiable? This was the same for all Me109's....so no data plate...
2118 is stamped onto the back, thus indicating the airframe it originally beloinged to. For sure it is not a part number, as the part number for the Access Hatch is 109-12...
.
Mike