Yeah Nils Grif makes them in Germany IIRC, and you can order them for $150 paid in advance and then wait three months or so.
I did a search and can't find a website for you, but I have a 455 4" and couldn't find any wood grips but those, when I searched two years ago.
Hogue, my source for most all wood grips doesn't make a wood one, I do have the Hogue rubber grip on my gun, and its decent, better feel to me than the ribbers that came with it.