My Howlrunner ship base has a lopsided firing arc, it points farther left than right, should I not use it because it is a manufacturing defect?
@OP
I think if you honestly want to see if those dice are better than other dice, you really DO need to roll them and collect data, written down, and a LOT of rolls. Not 100, more like 1,000 rolls each. Since they are all the same color, you will have to roll the dice 1 at a time, as you shouldn't mark them since it may affect weight.
Basing it off of visually collected data is very tough, and is prone to human bias.
On ANOTHER note, I would honestly just live with it, guys. This IS a game after all.
But if you insist on doing something, I would talk to the guy and say,
"People are still grumbling about the possibility that your dice roll better odds than theirs. I know it's not your fault, but I'd like to end all this talk. I don't want people to hold it against you when you win a match. Would you mind using a new set of dice for the next couple of events? I'll buy you a new pack just because of the headache we are putting you through."
That is about the nicest, most understanding way I can think to say that.