I have had the kingpins in different generation releases since they first came out. The one issue I could see you running into is the brake being such a large part of the binding that it may not function properly without it on there. Additionally, the part of the brake that goes under your heel would be missing which may cause you some trouble. If you have the brakes perhaps there is a way to put it on there, then put it into hike mode so the sides are up -- then you could clip the metal sides off to shave down the weight a bit. Just some thoughts.
That aside, you'll definitely enjoy them. The new generation is very well made. I had an issue with the first pair I bought and their customer service was excellent. Overnighted a new piece for them.