Walther Germany says no, but I'm not fond of shiny hardchrome anymore. Any advise?

You can have it bead blasted, will give it a dull stainless look.

Is there a reason that you don't sell it and buy a blue model?

May be cheaper to do that.

You could bead blast it and then use Gunkote on it. Gunkote comes in a number of colors and if done according to their directions is very durable.