It's not the strangest thing in the world to see an unreleased phone get a pre-launch update -- think way back to the Motorola Droid X -- and the Sprint EVO 3D is the latest to do so. Software version 1.13.651.7 will bring a fix for "Calendar entries in certain formats force close while editing." Important, indeed.
Oh, and look at that. Our review unit's already got the update. It's a sizable 26.59MB and installed with nary a problem. More in the link below, if you're interested.
More: EVO 3D forums; Thanks, anon!