Re: What would you do?
I'd say he WILL sell the ONE. And if he really wanted to, I'm sure Sage would take it back when it arrives for another model. There are lots worse things that can happen to a person than having a ONE arrive at the shop.
As far as between you and he....that's just something only you can know what to do. Go with your instincts I suppose.
All the romance of trout fishing exists in the mind of the angler and is in no way shared by the fish.