Replacement - I called CSMC after the RBL-20 ordering deadline had passed and was lucky enough to get on a wait list. CSMC emailed me last week to let me know my name was up if I was still interested. I called Mark and placed an order that day.
BTW, I just talked to someone at CSMC who said the case coloring was a more durable finish than the french grey. Not sure what this statement was based on, whether it applied to rust resistance, whether it was specific to the RBL-20, etc., though.
Some posters have suggested that a plus for case colors is that the gun will still look good if the case coloring wears away.
After listening to everyone's comments, I decided to switch from french grey to case coloring. Probably doesn't matter all that much for a gun that gets hunted, I guess.
--shinbone