I believe they will, I had some a few years ago and they did. I just got a new pair this week, and after I have upgraded my lights, I will get a BTA for them.
IMO, because a clown is tank-raised or wild caught, it doesn't make a difference whether it knows to have an anemone host. It's instinct. The question is whether or not they want one, and that nobody but the individual clown knows the answer to.
Well then I will jus have to ask them if they will host or not...LOL JK. Another question.. Are there any different types of Clowns that will get along with pair of percs when added?