The 606 GPG plate has 2 holes on top and 2 on the bottom, i just aligned both plates together and drilled 2 holes on MY FAST plate to match with the 2 holes on the 606 plate then screwed them both in the same hole.
Naturally, this question has a different answer depending on your state. California vehicle code has a couple caveats that would prevent this. 1) If you are issued two plates, both must be installed on the vehicle. 2) License plate size must be 12" X 6" with restrictions on letter size and spacing.
Good luck to the creative residents of the other 49, though.