"On the 747 (which I have less knowledge of, so Jumbo boy's correct me if I'm wrong!) the kruegers are flat when retracted, but on extension the flat section actually changes in camber as they extend. "
Can't vouch for the Classic 747, but the 747-400 Kruegers (inboards) are as described previously (flat with a folding nose, like a "J").
The outboards and midspans on the other hand, are Variable Camber (They also have a folding nose, but the longer flat section changes in camber when deployed).
Regards.
Q.