You can purchase them from any Honda dealer, but would have to have it shipped to a friend outside Cali. But here, if you order the Y-pipe for 2002-2005, they are ALL black with no cat, but the 06 & 07 are all stainless with a cat.
SO, if you find anyone parting out a 919 (like I did, right here on WT), as long as their bike has the flat black Y-Pipe, it's worth buying! This guy didn't even realize his had no cat until I mentioned it to him, then he looked and said "You're right!".
Found mine here in the classifieds from an 03. Last one I got for my 07 I found here on WT also, from a guy who bought his brand new from his Honda dealer but sold the bike before he installed it, so he sold it to me for $75 since it was still brand new in the original box from Honda.
As for punching them out with a screw driver, that's the ghetto way of doing it. You never really get it all out, and risk denting the ends and making the pipes not fit anymore. I'd just find a black one and offer the person $50 for a used one. That's a fair price only because a brand new one is only like $120.
To be sure you're getting the right one and the seller's bike is not a CA bike, just ask them what color the Y-Pipe is: black is good, stainless is bad.