The US version you're running is the correct level order (same as Funspot).
I think the original order of the DK screens was Barrels, Elevator, Conveyors and ended with the Rivets. It actually makes more sense when you play the non-US version since Kong is defeated on the Rivet screen.
I used to think the same, but am used to the US version. However, the Japanese version also behaves a little differently in places. For example, in the first Elevators, the elevators are slow, much like Crazy Kong. (I'm guessing Falcone bootlegged off the J set.)
Thinking about it all, the US set has an overall faster pace, as well as progressively introduces you to the game, which I can see more captivating to a US audience.