That's evidence of House's plan B; If Wilson doesn't believe the page, go to his room with a big bottle of wine, get him tipsy, seduce him and search the room for the guitar while he's sleeping off the afterglow. Wake him up with obnoxious power chords, 'cause he's cute when he winces with a hangover. Pet him and crawl back into bed.

House was actually rooting for plan B; hence his grumpy manner on the phone.