If you are looking for the real thing, its called a "Nintendo Lower Marquee / Top Bezel Bracket" and it can be found at
MikesArcade.comHowever, if you are looking to make you own because the original will not fit, you can see how I did it for my
Mini Donkey kongSpoiler Alert: I just used Drywall corner bead for the lower part and drywall bull nose cornering for the top. (Had to bend that one open a little) Then used magnets to hold the bezel on.