Actually, not really. Ubisoft does not force Uplay on their third-party developers. Call of Juarez: Gunslinger, made by Techland, is Steamworks.
That + the fact that the game has Steam achievements and that Ubisoft already confirmed that the retail release is steamworks (http://blog.ubi.com/south-park-the-stick-of-truth-release-date-grand-wizard-edition/ see on the comments)