On a $10 strike, there's a clear visual distinction between the silver and the brass rim. On a $300 strike, the copper rim is silver plated, so the entire thing looks silver. If it was marked .999 on a $300 it would be very easy to mistake the entire thing as silver. Everyone has seen sellers with their claims that $10 strikes are solid silver, or the rim is gold, etc. Just imagine all the claims on $300's if it was stamped .999.

The best example was Pam Martin in this thread above stated the $300 is the same as $200s. Look at her experience with strikes and she still was confused. I think Gaming made the right call based on how the $300 is made.

Dave.