Yeah, it should be 7/16". A med extention and a 3/8" ratchet should do the trick if you can rotate the prop to take bolts off when they're on the bottom... Bring a long wrench in case you can't... They rust up pretty good in the northern states. You'll usually need prybar to get it out of the yoke. I take it you're flat towing it home...
Since it's been brought up a lot lately, be aware that when you yank the prop out of the t-case, it's going to spill some fluid. Please make an effort to catch it, or things will continue to degrade as far as doing minor checks/repairs in the GL lot... If they won't let you work on it in the lot, it's Ok... you can drive or drag it out even with the bent prop, just keep the speeds below 25mph or so... (They usually aren't bent really bad. The worst of my trucks was out about 1", and it didn't vibrate until about 25mph.)
Good luck!
C