The 81 KZ650H1 did come stock with the accelerator pump installed. I prefer my bike to be bone stock as possible, but they've really been nothing but a pain. The rebuild wasn't too bad compared to any other carbs, but there aren't any "all in one" rebuild kits available, so I'd stick with what you have. And good luck finding any air ducts for the h1 carbs as well.
You could pull the carbs and air box off the H2/3 (82/83) which should work as well, with the added benefit of air ducts still being made (14073-1032)