As seen in pictures on the web the SEALs had great leeway with their choice of uniform. They were seen in Beo Gam, Tiger Stripe and ERDL camouflage, blue jeans and a few in VC "Black Pyjamas". These items were often mixed and matched by personal preference.
The box art figure is painted in an all ERDL pattern uniform. Looking closer at the combat shirt, its details make a Tiger Stripe pattern more appropriate. The ERDL uniform was manufactured using the 3[sup]rd[/sup] pattern jungle uniform and all the buttons were concealed. The figure's shirt has exposed buttons found on the 1[sup]st[/sup] pattern uniform that were made in Tiger Stripe. The addition of concealing flaps to cover the buttons would convert it to the later style uniform for the ERDL pattern.
The vest he is wearing is a modified Mil-C-29105 Coat, Ammunition Carrying, Buoyant, and Bladder, Flotation. They came in three styles, Rifleman (that the figure is wearing), Grenadier and Radioman. It was made of rip-stop cloth in the ERDL pattern and had an inflatable bladder that could be inflated with a CO[sub]2[/sub] cartridge or orally. It replaced the black life vest they wore early in Vietnam that provided a large black aiming point that covered all major organs. Many SEALs didn't wear the coat as they felt it was to hot and restrictive. Those that did, often cut the sleeves off as shown on the figure.
The pants as depicted also do not lend themselves to the ERDL pattern. First, is the exposed buttons. Second, is the small pocket below the large thigh pocket that wasn't found on ERDL patterned pants. That pocket could be carved off and a concealing cover added to the pockets to use the ERDL pattern. Use them as is and paint them in Tiger Stripe. Or, they could be painted as blue jeans as SEALs sometimes removed the outer pockets from the combat pants and had them sewn on to their jeans.
Many people wonder why a unit that depended upon blending in with the environment would wear jeans in the jungle. It was largely a matter of personal preference. Many SEALs never wore them as they felt they were to heavy when wet, took to long to dry and when muddy they stiffened as they did dry. Others swore by their jeans. They found them more comfortable, they didn't make the swish noise that the combat pants did, they were resistant to tears and nearly impervious to the many biting insects in the jungle. Regardless of the type of pants worn, skivvies were seldom if ever worn. However, some did wear panty hose to ward off leeches.
There was also a difference in styles between SEAL Team One and Two. Team One was known to be a little more "rock and roll" with more variance in their uniforms. Team Two was more "regulation" (SEAL regulation, not Marine regulation) and were more often seen in issue camouflage clothing.
Cheers,
Rich