The soviet military equipment isn't all that Soviet ... e.g. the helicopter is supposed to be a "Mil-Mi 24 Hind" (Pilot and system operator sitting behind each other), in fact it's just a French "aerospatiale puma" with additional mock turrets and so on (crew sits side by side).
Peshwar, Pakistan, actually was the site of many refugee camps and Afghan rebel support, and American intelligence operated out of nearby Islamabad, and the muhajadeen operated principally in the supposed "50 miles over the border." Especially considering the movie was filmed in Israel, the geographical shots are also pretty accurate, with only one problem: when Rambo says "across the valley is the border," across a plain with mountains in the distance, they are supposed to be escaping into Pakistan. There is only one spot where they could be, and it's right in the middle of the Khyber Pass, inaccessible to Russian tanks and armoured vehicles. The Russians would be riding on donkeys, not tanks. The only such place near the Afghan border that such a battle could take place would have Rambo and Trautman escaping into Iran.