I'm not qualified to comment on the legal basis for the suit, but the publicity has to be great for both joints. I can just imagine the two owners, over a slice and a beer, plotting this stunt to drum up publicity. The next step is for them to agree to settle their differences with a shoot-out, where local luminaries will judge whether they are identical and who has the best. And regular folks who visit both pizzerias will get to vote too. And then they'll make it annual event.
I've gotten so cynical.