My plan was to go to the legion deal with Benny and on my way back open that truck I saw over looking the town of Cotton wood unfortunately only 25/50 lock pick so wouldn't let me :C so i had to leave it

http://fallout.wikia.com/wiki/Cottonwood_Cove

And why don't you just try it and find out for yourself?

my lock pick isn't high enough and im using my level up on speech and barter since i hit 100 science and 70 guns

also the wiki only tells you what the truck says when you try to open it I want to know if opening it = end of Legion or just a pissed off faction do they even know was the player that opended the truck if doesn't = end of Legion ?