What can you tell me about Krieghoff guns?

I'm sorting threw my grandpas guns that he left me & came across some Krieghoff shotguns and what looks like a double barrel rifle to me. I found their webpage but they dont have prices. There's 5 shotguns so far and that double barrel thing. The medal looks messed up though, all kinds of different colors that wont wipe off. I think the oil has damaged the gun and changed the color like that. Will that effect the value much if these are worth anything. Theres some shotguns made by baretta and something called an AYA that dont have that colored medal.