I'm pretty sure I had two lucky coins during a single game: one from Grubby and one from the random loot. It may be my memory acting though. Otherwise I don't think it's possible.
Dang that sucks, I'm on a quest to hold every single artifact at once, and I lost the Lucky Coin at 1500 when my bubble ran out and I didn't notice. 6000 meters later, I still haven't seem another Edit: 6500 meters later https://imgur.com/G8N0Bdu
Ok, so this is SUPER late, but I'm almost positive you can't get 2 lucky coins, unless I'm just SUPER unlucky. Just trying to clear up some confusion. @bscotchseth