A guitar owned by Pat Smear — and played by Dave Grohl in the Foo Fighters’ “Monkey Wrench” video — is being put up for auction in the U.K. Smear purchased the customized Gretsch White Falcon in 1996 in Los Angeles, says Foo Fighters guitar technician Earnie Bailey. “Soon after, I replaced the Bigsby tremolo system with a gold Gretsch Cadillac style tailpiece at Pat’s request, as it provided better tuning stability,” Bailey says. Smear often played the guitar while touring with the band, Baily adds. The guitar is expected to hit the auction block at the U.K.’s Gardiner Houlgate auction house on September 7th. Are guitars that were once owned by rock stars who are still alive worth more than their normal prices?