On one hand, the games haven't been in arcades for a long time and are practically worthless to operators, so they'll tend to be rare. On the other hand, Asteroids had a huge production run, and there are still a lot of games out there. If you see an Asteroids machine at an auction, you'd know not to bid very high because the game is relatively common. It'll show up at another auction sometime soon. On the third hand, Asteroids Deluxe had a fairly small production run and was never as popular as the original game, so you should probably take advantage of the opportunity to buy as soon as it arises.
Bidding wars are bad news.
Remember, if you need a rationalization to avoid bidding on a given game, or you want to console yourself after losing a bid, remember that there are other auctions, any one of which might also have your game in it. We highly recommend this as a way to pick up your first machine. If you've never been to one, go to one and sit through the whole thing. It's good experience, and you don't have to buy anything. For the most part everything works and will work when you get it home, but there are no guarantees.