Most (if not all by now) Courtyard's are 2.5*s. You can not bid for a specific hotel -- there is absolutely no way to be sure Priceline will put you in the Courtyard. In LAX I would think the chances are marginal because there are so many hotels nearby (you can sometimes be reasonably sure in small areas and/or areas with one really nice hotel, etc).

If you want to stay at the Courtyard for sure, definitely don't use Priceline. If you want to save money and stay at any hotel of a similar quality level, then Priceline may be your best bet.