I've got a burgundy horn button/ring assembly on hand for $50 shipped. You'll need to swap out your medallion for the one on this button, but the ring is not cracked or damaged whatsoever. Removing a 20+ yr. old button from it's original ring is also tough due to the 2 retaining metal clips on the rear of the horn ring being so small. The above listed price also included a fresh coat of grey interior paint on the button & ring so as to give you a nice, new appearing part for your ultra rare WH1. Thanks.
I bought one on ebay a while back that was billet aluminum and painted to match. Has the textured finish and looks just like the original one, and won't crack. I think I paid 90 bucks for it and it came with the GN center.
It's removed via the two allen screws at the left and right of the ring. The rest are fake. The horn wire(under the button) is a twist-lock(bayonet type) affair. Don't over-tighten the screws on the new one. That's what causes the rings to crack (usually).