That was hilarious! Clark is so paranoid about keeping his secret, and having the alternate identity... and everyone knows!
It makes a lot of sense when you describe it, too. Of course Henderson would know after the gangsters "shoot" Clark. Of course Perry would figure it out - he didn't get to be EIC of the Daily Planet because he could yodel. Of course Bobby Bigmouth would know - he's a profession snitch and information is his business. Of course the Smallvillians would all know.
Frankly, though, I am surprised that Jimmy figured it out.