How can I tell which revision MD is mine?
You need to open it up to be sure. But here is a nice guide:
http://www.sega-16.com/forum/showthread.php?7796-GUIDE-Telling-apart-good-Genesis-1s-and-Genesis-2s-from-bad-onesIf it boots straight to the game (without the licensed by Sega nonsense) then you're good. But even units with that screen can still be good.
For JP Mega Drives, look at the SEGA logo on the bottom right corner of the console (it's right next to MEGA DRIVE). Does it have an ® after the A in SEGA?
Motherboard revisions:
-With an ® next to the Sega logo: VA0, VA1, VA2, VA3, VA4
-Without an ® next to the Sega logo: VA5
Bottom line, either way you should be good as long as it says AV Intelligent Terminal/High Grade Multipurpose Use. If it doesn't, it can still be good just as long as it's not a VA7 (the last version that comes in that shape).
Looks like yours is the SEGA® model so you're definitely good!