IIRC, when Scale Auto did a review of the Trumpy kit they noted that the chrome had a copper undercoating, just like 'real' chrome.
It may be almost impossible to strip the chrome plating with out ruining the plastic,
I'd spray the parts with a good primer (Tamiya, maybe?) and then paint to suit.
Also, what colour are you planning on painting the de-chromed parts? If it is a different shade of chrome, I might try different clear flat paints to see what finish I could get.