Finally, hirsute World Series heroes David Ortiz and Shane Victorino are clean shaven. The bearded Bosox, joined by Boston cop Steve Horgan, shed their shaggy facial hair Monday morning at Gillette’s world headquarters in South Boston. The “shave off” was partly promotional and partly charitable, with Gillette donating $100,000 to The One Fund, created for victims of the Boston Marathon bombings. “Oh, my goodness,” Victorino said when he glimpsed his soft-as-a-baby’s-bottom face in the mirror. “It’s like I’m 12.” Horgan, who was in the Sox bullpen and raised his arms triumphantly after Big Papi hit a dramatic eighth-inning grand slam in Game 2 of the ALCS, delighted the crowd Monday by raising his arms just as he did that night at Fenway. Also getting a shave was Michael Grant, a bearded Sox fan from Leicester, who was chosen from Gillette’s Facebook and Twitter accounts.