As you're also hearing over on the Hide (and Blaserpro too?), the Mk4's are good to go. I've had several, older and newer, and have never had a problem. I suppose if you actually drive over them with the Humvee, you might have to rezero, but I've never had to, even after harder falls that I care to admit to.
I'm about to pick up yet another (the new FFP design), and I have no doubt it will meet Leupold's earned reputation.