The matt black marks easily because matt finishes are rough and pick up material from other surfaces when they rub together, matt surfaces also mark where abrasion takes off the high points from the rough surface and brings local areas closer to a gloss finish.
The Umarex gloss finish is a matt base with a clear top coat, the clear top coat is "just painted on".
The later matt finish doesn't come off with Nitromorse, Cellulose Thinner, Acetone or Trichlorethylene so it's way better than most paints
ATB,
Nick