Ken,so glad to read that yours fit. I know our stackable was a tight fit. We had the dealer install it. We love it. To my knowledge the Closet is the same size they have always been. I know it was a bit difficult getting ours in. They had to remove molding, doors etc. We vent straight back though in ours and don't have to go to the side wall. I'm sure that was easier that how you had to do it. When they installed ours they should have removed the door handle on the inside of the closet because it hits the dryer every single time and has caused a dent in the front of it. It took me the longest time to figure out what had caused that?
Our friends, Jim and Karan (MOC members) have a 3400RL and they have the same closet you do in yours. They had a stackable unit. My sister has a 3400RL and her doors already bi-fold, so maybe they changed that now?
Enjoy your new Montana and congratulations on it.
We hope you have as many happy hours and miles as we have had on ours.
Patty