The only issue I can see is if you need to replace the crankshaft. The knurl at the rear seal is rotation dependant. You cannot use a standard rotation crank and just drop it in place. You'll need to have the knurl changed to reflect the reversed rotation. Ignore this and you'll never get the oil to stay in the crankcase. I learned this from first hand experience.

If you can re-use the original crank, that'll save you a huge headache!