They won't get as tender, but they'll get just tender enough. They'll still have some "bite". The meat will cling to the bone just a little. The problem with not foiling is that you really need to be dead on accurate with your temp and when you pull them. Leave 'em on a little too long and you'll get a tough leathery exterior and a dry interior. Pull 'em off too early, and they'll be rubbery and tough.
The best ribs I've ever eaten are done with no foil, but the pitmaster's some sort of bbq wizard. I decided to try and do it the way he does, but I've failed time after time. I finally had to man up and admit that I needed a little insurance. Foiling gives that insurance. One hour will tenderize a little, 2 hours will give you that falling off the bone consistency that most love but I don't. The time after foiling firms them back up and dries them a little.
On my last smoke, a 2-1.5-.5 method was almost perfect. I think one hour in the foil would have given me perfect consistency for my taste.
Good luck and don't forget to share the Q-view!!