It might be worth asking the locals when the bucks typically shed their horns, I've added a pronghorn tag onto a deer hunt in Montana before in late October and I was having trouble with bucks already dropping one or both horns. I was stalking a nice buck and in the half hour it took to loop around he managed to drop one side, but luckily he found a buddy in that time that still had both his horns and I ended up with a 79" buck. I met a few guys driving around that had shot bucks that day and they had already dropped their sheath. If the ranch is filled with pronghorns you should still find ones intact so I'd get the tag, but want to make sure you know what you might find when you get there.