I'd still get which ever one you get from them. Then tell them thanks, and that you understand the reluctance to get a one.
Personally I would be reluctant as well. It's a 4 wt. It's a One.
I'm sure he has a pretty darned good idea of what gets sold and what sets there gathering dust.
Good fly shops are a great thing to have. Even married people don't get along 100% of the time. As I said, I see why he didn't want to get it. I'll bet if it was a bigger weight he would not have minded. Funny part is, knowing Sage, it is a bigger weight.