There were animal-rights protesters among the fans outside Warner Bros.’ “The Hobbit” preem, which may account for metal detectors at the Ziegfeld Theater entrance.In his pre-screening comments, Peter Jackson acknowledged the pressure of trying to correctly name from memory all 13 of J.R.R. Tolkien’s dwarves, which he got right as the corresponding actors took a bow. At the Guastavino’s afterparty, Martin Freeman, who plays titular character Bilbo Baggins, explained what a hobbit actually is: “I don’t know where Tolkien got the name but it’s idealized Britishness, a creature who dwells in Middle-earth. Hobbits are like farmers who want to till the land and go to the ale house and have a nice life, and in terms of the story the hobbit is us.” At 6 foot 3, Richard Armitage, the film’s dashing warrior dwarf leader Thorin, is anything but small. “We left it to Peter to do the digital work,” said the thesp. For Andy Serkis, whose performance-capture work as Gollum ushered in a new aspect of acting, it’s time to take a final bow with the emaciated schizoid cannibal. “It has been a watershed in my career because that technology has evolved over the course of 12 years. I was around in the right time,” he said. As for really saying so long to Gollum, “That’s his story in the book,” Serkis allowed. “Having said that, never say never with Peter Jackson.” Among those seen mixing it up at the party were Liv Tyler, Ben Affleck and Elijah Wood.