A lot depends on the ball its self.
Usually, a symmetric ball only needs to be weighed out in order to tell exactly where the topweight ends up after plugging, and how much of it there is. Once this is done, you can drill it accordingly.
On an asymmetric however, the MB marking may not be true after a plug job, and the ball probably should be spun on a device called a Determinator to verify the true MB location before you re-drill. Once you know the true MB location AND the topweight location and amount, you can re-drill it with confidence.
The one, and ONLY, 800 series I ever shot, was shot with a used ball that I had plugged, then it had a small crack start (that I had drilled out and plugged as well). Two months later, I shot 812 with the thing.
Long story made shorter, yes, plugged stuff is fine, as long as it is done by a shop that knows what they're doing, and cares about quality.