My dad picked up the lifters from Dino today. Not too surprisingly, Dino did find a tiny amount of damage to the valves in cylinder #5 (where the nut spent most of the time). The valves were bent about 1-2 thousandths, probably caused by the nut getting pinched between the top of the piston and the partially open valve. Dino reground the valves so that they will seat properly in the head.