Only go on one way....but the 'open' part of the shackle needs to be facing the front of the truck.
IDK the proper way to actually bolt them to the rig.....when I did mine, I got the old ones off, springs hanging, then bolted the top of the shackle in the hanger, leaf into shackle, both those bolts threaded but not tight all the way. Then I set the truck on the ground. Jumped in the bed a few times. Then tightened everything down.
Is there a 'proper' way to tighten/install shackles?
Here's a pic for reference...