You'd be surprised how many people are clueless about differentials. I test drove a 2014 Silverado at the Texas State Fair, and asked the Chevy rep who was riding with me what the diff ratio was in the truck. Not only did he not know, he didn't know what ratios were available. In fact all he could tell me about it was that it had an auto e-locker (which is badass by the way). Most of my friends have no idea what type of diff their trucks have either.
Anyway, to answer your question here is a link to an article on Allpar that talks about the LSDs. Its in the axles section in the last paragraph.
I was also excited to find that they went away from clutch pack LSDs in the 2013s since my truck has the 3.21 LSD rear. In my opinion clutch pack LSDs are more trouble than they're worth.