Suzuki 2 Strokes

Your 72 GT has three individual carbs, with a single throttle cable that splits 4 ways for carbs and oil pump control. The later models had the carbs mounted to a common yoke that used two throttle cables, push-pull variety, that required a different control unit as well. The carbs may work quite well if installed, as the jetting didn't change much over the years, but, they are physically larger, and may not adapt to your airbox, among other considerations. You are probably better off to source out the early components that are missing. Who knows, someone on this board may have exactly what you are looking for. Good luck. They are a great looking bike, and fun to ride. Cheers.
Fred

+1 Fred. Also the head is different on the early models and the overhang will not alow you to mount the later style carbs. If I were you, I'd source some correct carbs for your model. They show up on ebay from time to time.