I'm not up on TG specifics and what they do or don't accept scores for, but I don't believe this board had/has the hard ROMs. There are the v2 easy ROMs (which also have a hard setting option, via the dip switches), and then there are the original v1 hard ROMs. I'm pretty sure this board has the 'easier' v2 set, but those scores are insane either way.
I keep telling myself they must have used some point-pressing trick or other technique to get those scores, as I find it very difficult to believe you could get a score that high through 'normal' gameplay. The difficulty ramps up pretty fast once you hit around 50-60k, and keeps going as far as I'm aware.
I also know the hard ROMs are not identical to the easy ROMs set to hard, as the behavior of the alien ship is different between the two. There's a good thread about it here:
http://forums.arcade-museum.com/showthread.php?t=372787
And yes, I agree about game prices. AD is my 'desert island' game. I never get sick of the gameplay. It perfectly exemplifies the 'easy to understand, difficult to master' ethos of Nolan Bushnell and Atari at that time, and is a perfect sequel.
It kills me that this is still here. Refurbed and warrantied board, owl eye coin door, anti-glare kit, and it's in great shape. This thing is pimped out. $500 is a steal.