Most Cogies Mausers I have seen in this country were pretty plain, but have sttep price tags on them due to the Owner thinking anything British is quality. I typically see .375 and .404 Cogiie Mausers though. Their asking price usually starts ~$4000-4500, and stay on the shelf for a few years when so priced. What thier final "getting" price vs. their "asking" price is, I have no idea.
As the saying goes, judge each gun on its own merits. Without seeing the rifle in question, we can not give you a good price. Just as a SWAG, I woudl say asking price would be anywhere from $3k-4k. How long it site on the shelf depends on how willing the owner is to deal.
BTW-for the money I see on Cogie tags, you can usually buy a lot more gun made from someone else.
Oh, one more thing. I have noticed that many, if not most, C&H rifles have very light colored stocks. I wonder whay that is? Anyone have any ideas?