Combine oysters and buttermilk in a large shallow dish or zip-top plastic freezer bag. Cover or seal and chill at least 2 hours. Drain oysters well.
Combine flour and the next 8 ingredients. Dredge oysters in flour mixture, shaking off excess.
Pour oil to a depth of 1 inch in a Dutch oven; heat to 370°.
Fry oysters, in batches, 3 minutes or until golden. Drain on paper towels.
Split rolls. Spread 1 tablespoon mayonnaise evenly on cut sides of rolls. Place 1/4 cup lettuce and one-fourth of Buffalo Oysters on bottom halves of rolls; cover with roll tops.