Mil Mi-24 Super Hind Mk. III comes with upgraded countermeasures, weapons and avionics (top pic). Mil Mi-24 Super Hind Mk. IV comes with Pall Vortex Particle Separators to protect the engines from debris like snow, dust, salt water (bottom pic).
The AC-130H Spectre (Attack Cargo Plane Project II) currently retired/replaced with the J model Ghostrider. Spectres weapons consisted of twin 20mm cannons (mid pic), one Bofors 40mm cannon and one 105mm Howitzer (bottom pic). See the top pic, there are two black squares that used to house the 20mm cannons. This weapon was removed due to a ricochet issue (collateral damage) reported by Special Forces on the ground, something that has never been mentioned anywhere.