The cassette tape that Eddie grabs is Iron Maiden's "Piece of Mind," which was released on May 16, 1983. The band responded favorably to their inclusion in the scene, posting "We're with you, Eddie!" to their various social media accounts along with a still image of the scene.
Assuming the War Zone surplus store sells firearms legally, the legal age to buy firearms and ammunition in the US since 1968 is 18 for rifles and shotguns and 21 for handguns. It would be illegal for Jason Carver to buy a handgun, let alone pistol ammunition, from a licensed firearms dealer unless he is supposed to be a 21-year-old high-school student.
The recreational vehicle that Eddie breaks into and hot-wires is the same RV that Nancy knocks at and tries to interview their owners in Episode 2.
Yuri's helicopter, "Katinka," is a Kamov Ka-26, a Soviet light utility helicopter often used for crop dusting.