Not really. The Tamiya kit represents a protoype Sheridan and that one only wore OD. A good match for US 1960s OD is Tamiya's JGSDF Olive. It is darker and less green than their normal Olive Drab paint. It is available in spray cans or jars. The JGSDF paint is very similar to the old Pactra dark OD too.
Even if the Tamiya kit were not a prototype, the Sheridan in Vietnam was always OD so you would still paint it the same. Vietnam tanks had a different gun, sight, storage bustle, commander's cupola, etc.
The Sheridan was not widely used in the US arsenal. Some modernized vehicles were used in the first Gulf War but they are considerably different than the Tamiya kit, with a different gun, sight, commander's cupola, armored gunner shields, etc.