Rulebook answer If the OEM part numbers are the same then it is legal.
reality no, no, no, and more no
can't use the 2nd gen case cause it is different
can't use intake cams in exhaust, that is not how it came from factory
can't change carb to FI or FI to carb
you can't pick the best parts from a model line to make your own version, in most cases later years have better running gear, systems etc but some models have price reducing revisions that result in a lower quality part used.