Preheat the grill or broiler.
Using a pastry brush, spread the inside and outside of each bun with melted butter. Grill quickly to warm through (alternately, place on a baking sheet and run under the broiler). Remove.
In a bowl, combine the mayonnaise, truffle oil, lemon juice, and salt, and mix well. Fold in the celery, shallots, chervil, parsley, and chives. Fold in the lobster meat. Place 1 bun on each plate and divide the lobster salad among each. Serve immediately with potato chips.