Lawyer needed

Do any of O's old law-school friends still read this blog?  I could use a bit of legal advice.  Yesterday I forgot to move my car for street-sweeping day and got a ticket.  Or at least a ticket was left on my car—a sloppy cop wrote the correct license plate number on it but the wrong state ("MO" even though my car is registered in Texas).  Now it's possible that I could just ignore the ticket and hope they realize they made a mistake and dismiss it without trying to track me down.  But I was parked in front of my apartment building, so they wouldn't have too much trouble finding me if they wanted to.

Here's what I want to know:  Could I successfully contest the ticket on the grounds that it was incorrectly filled out?  Is that technicality enough to get me off, or would the fact that I showed up contesting the ticket constitute prima facie evidence that the offending car was mine, allowing them to prosecute anyway?  (Also, is there a free website that would tell me whether there actually is a Missouri license plate with the same number?)  Twenty bucks are at stake here!