I believe so, it's a front flipping skill with no hands a la front tuck. A person on one of my teams (lvl 3) competed it not too long ago so I don't see why it wouldn't be?
Flips:
Back Flips may ONLY be performed in tuck position only from a round off or round off back handspring(s).
Exception: Aerial cartwheels, running tuck fronts, and ¾ front flips are allowed. The following tumbling skills are examples of skills not allowed: X-outs, layouts, layout step outs, whips, pikes, aerial walkovers, and arabians.
Clarification: A front handspring (or any other tumbling skill) into a front tuck is illegal.
Other skills with hand support prior to the round off or round off back handspring are allowed.
Example: Front handsprings and front walkover through to round off back handspring back tucks are legal.
Cartwheel tucked flips are not allowed.
So, from the above, Aerial walkovers are specifically not allowed in level 3.