To my (very limited) knowledge, yes. if by symmetric you mean symmetry condition, so u*n = 0 at that boundary.
The way I think of it is that W.sub(0) ‘accesses’ the vector space for velocity, and then W.sub(0).sub(0) corresponds to the horizontal component while W.sub(0).sub(1) gets to the vertical component of the velocity. Since your boundary 1 is vertical, the normal direction aligns with (minus) the horizontal component, so setting W.sub(0).sub(0) to zero is the way to go.