If the shocks are not angled some direction, you'll lose a small amount of travel. The shock needs to form the hypotneuse of a right triangle to get the most movement through the range of motion of the rear end's up/down travel. If the truck is lowered, you're not going to get much suspension travel anyway, so the shock is just on there for decoration. Put it anywhere it's convenient- - - -it's not going to function well no matter how it's mounted.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!