Yes, but the weird thing is that before you call unveil, everything is already unveiled, which is not in sync with the dictionary definition of unveiling. I hope a better name is found.
Your comment made me try to look up the exact semantics of unveil(2). It was a bit hard to find (I could only find something on its predecessor pledgepath), but apparently, unveil doesn't take effect immediately, but only at an invocation of pledge(2) (which usually follows immediately after it). That was not at all clear from TFA.