You did well! The parts may interchange, but there were differences and some parts don't.
Basically, the B anc C are similar, but the C is wider (C is a two row tractor, the B is a one row). The B usually has the non-adjustable wishbone front axle and the C is either tricycle or adjustable wide front. Other than that, they look almost the same. They do have the same engine and trans. Taking the parts from one of the electric start C's can make the B an electric start, but it will be a LOT of hard work. My B is hand crank and usually starts with just a couple of pulls, even in colder weather.