Anyone know what size bolt for front driveline to T case?

[AirSpeed]

Last summer I noticed I was missing a bolt in the yoke on my front driveline on the transfer case end. I totally forgot about it until a couple days ago when it snowed. I only want to crawl under there once since it’s surrounded by snow, not to mention I broke three ribs last week slipping on ice, I hurt and don’t want to spend much time under there in 14 degree weather!
I don’t want to go buy a bunch of assorted bolts only to find I got every size and length but the one I need! Appreciate anyone who may know! By the way, it’s a 72 GMC K1500
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