It's definitely possible. I collect eggs twice a day, morning and afternoon. I recently acquired two commercial leghorns. While they were in quarantine, twice now I've gotten three eggs in one day, meaning one laid two eggs. Both times I've been able to easily ID the second egg, because it had a thin, almost semi-translucent like shell. Hard enough that the egg kept its shape and didn't break, but still a very thin shell. Up until that point, I was on the side of the naysayers, saying it wasn't possible. And in the three years I've had chickens, the leghorns were the only chickens I've had that have done this.
Golden comets are bred for production, so my assumption would be production breeds can on, a rare occasion, lay a second egg.