I dont think it was the same guy.
I too saw a guy with a guitar outside the El Rey, but he had Matt Groeing draw a Homer Simpson on it.
I am pretty sure the guy just brought the pick-guard, and had King sign that.....I mean, why tote a whole guitar down to have the pick-guard signed when the pick-guard is removeable?
Not really...King plays the guitar, and this was signed at a concert that King was performing at.
He is also an avid Red Sox fan, which is why you see King signed baseballs.
And I just checked the auction, and someone allegedly just bought it for $1,300.