I don't own a Wildcat, but all F18's have some type of inward angle built into the tiller portion of the rudder to provide ackermann steering geometry.  This creates a left and right rudder assembly.  I'd guess most if not all other aspects of the rudder should be symmetrical.
With regard to ackermann, in simple terms, during a turn, the rudder on the inside of the turn is at a sharper angle than the one on outside of the turn.  The benefit on a catamaran is to reduce drag during the turn.  
https://en.wikipedia.org/wiki/Ackermann ... g_geometry