Quoted from KenLayton:First picture is 6-32 by 2" long (maybe 2.5" long) machine screws.
Second picture is # 4 by half inch long tapping screws.
You can buy both at either your local Ace Hardware store or your local Tacoma Screw Products store.
Pop bumper caps are 4-40 machine screw into a post, unless they've been de-jumpered