The 199 crank is the shortest-stroke AMC six crank, and is apparently made from a better steel alloy than 232 cranks. 199 rods are longer of course. There's some rumor that there were forged 199 cranks but there's no evidence for that.

Barney Navarro based his turbo indy motor on the 199, not the 232.

http://wps.com/AMC/Navarro-turbo-motor/index.html#CRANKSHAFT

But anyways the cranks are out there; and "no one wants them" because of the short stroke (everyone's building strokers it seems). There weren't too many 199's I think compared to 232's. Not sure how you'd tell what's in a sealed-up motor.

The will of course be the earlier crank pattern.