Both the border post and the ambush by Bashirovs goons don't happen in BSM, I think there was a problem with the scripting engine but only R@S really knows.
The rebel camp can be uncovered by talking to the new librarian in Sagrada, but buying his other map is a ripoff, it will be uncovered by following the Sagrada police missions.
Which reminds me that one the first quests you should do in BSM is the drunkard in Santa Maria, he's a free merc, has a car and your luggage, and will talk to the Sagrada police for you
