Preheat oven to 400 degrees. Reshape crust edge to form high-standing rim. Bake crust until browned, pressing bottom and sides of crust occasionally with back of fork, about 14 minutes. Cool crust on rack.
Reduce oven temperature to 350 degrees. Whisk pumpkin, sweetened condensed milk, sour cream, 1 1/2 teaspoons cinnamon, 1/2 teaspoon ginger, vanilla and allspice in large bowl to blend. Whisk in eggs. Pour into crust. Bake pie until filling is puffed around the sides and set in center, about 55 minutes. Cool pie on rack.
Beat whipping cream, sugar, 1/2 teaspoon cinnamon and 1/4 teaspoon ginger in bowl until peaks form. Serve pie with dollops of whipped cream.