Heh, I was writing my post when you made yours and I see we both made a distinction based on the advertising and game resource things. Great minds!
I've also encountered at least one PC Engine game that has a tracklist printed on the back of both the case and booklet and at the time thought how that should probably be cataloged on VGMdb as well. I'd like to see it happen for the games that really seem to indicate that you should consider the disc to also be a soundtrack CD.