Coy, cloying and precious just for starters, this seasonal tale is about a 9-year-old boy who desperately wants a BB gun for Christmas. For all its drawbacks, the movie has charming moments. It's adapted from Jean Shepherd's novel "In God We Trust, All Others Pay Cash". Real People co-host Peter Billingsley, 11, plays the boy with grown-up sensitivity - he's efficient but not really a cuddlesome child performer. Darren McGavin, as his father, overacts no more than usual, and Melinda ("Close Encounters") Dillon, as the boy's mother, lends some sweetness. So does Ian Petrella, who protrays Billingsley's whimpery little brother. There this is pleasant fare as far as holiday films go nowadays, which isn't very far. (PG)