Is there anyway to tell the difference between Sebaes and Clarkiis?

[TGIF]

My LFS sold me two clowns and stated they are sebaes. I am new to SW and didn't realize that clarkiis are usually sold as sebaes.

Is there anyway to tell the difference for sure? I've been reading on line about a rough "S" shape pattern on the back stripe that goes into the dorsal fin for sebaes. One of my fish has this and the other one doesn't appear to.
thanks!

 

[elegance coral]

A. sebae

A. clarkii

Note the absence of a third stripe on the sebae