GOPLAT is short for Gas and Oil PLATform.
Ever since before 2011 U.S. Military Special Operations Forces started wearing the 4 tube Panoramic Night Vision Goggles (PNVGs) that provide a wider field of vision, and depth perception as to not run into walls, trees, obstacles.
PKM - Soviet made PK belt-fed machine gun chambered for the 7.62×54mmR cartridge, introduced in 1961 and was/is the Russian equivalent of the United States' M60 7.62x51mm NATO belt-fed general purpose machine gun.
This episode takes place 6 months after the events of the Season 1 finale.