lets try to cover all scenes

So surfing board - they go on surfing while there is attack on the beach - Air unit have couple surfers and in Captain Willard unit there is famous surfer Lance so they surf during combat
Riffle - Captain Willard and his units use same riffle
hat and hand grenade - while attack on the beach one helicopter is on the ground, woman approaches with hat in the hand. There is hand grenade under it and she throws it inside the helicopter together with hat
playmate sign - there is party for soldiers where they appear

also cast is so good
we have Martin Sheen - Charlie Sheens father
Marlon Brando
young Laurence Fishburne
Harrison Ford
and Dennis Hopper