I have learned that at least two packages, SUNWaudioemu10k and SUNWaudiosolo, are not part of the "standard" ("entire?") install of OpenSolaris b131. If you're looking for either of these, you should do "pfexec pkg install SUNWaudiosolo" or "pfexec pkg install SUNWaudiosolo".
Hopefully we'll get this sorted out before the next official release.
Update: Apparently (according to the expert I talked to) this problem only affects systems updating with pkg image-update. If you install a fresh system, the audio packages should be installed.