Mine is a 2012 with ~70K on it. It only rattles every so often after the oil has about 2500 miles on it. I bought it used and have changed the oil about 3 times with the Pennzoil full synthetic. The truck had a tune on it when I bought it, so god knows what the previous owner did to the truck before me. I also take trips where I am 1000's of miles from home, so I tend to be overly paranoid about these types of things. I want to do whatever I can to prevent a mishap while I am far from home. Also, I don't want to damage the engine by continuing to run it with an intermittent rattle - Just doesn't seem right in my opinion. From my research the 2011 & 2012's seem to have this issue the most. There were updates to parts involved, the phasers, VCT solenoids, guides, etc. which were implemented going into 2013 and newer from this generation. If your truck is not making the noise, I would not worry about it. There's plenty of trucks on the road that don't have this issue. I would however keep it in the back of your mind, that there's a possibility you may encounter this. Is it a ticking time bomb, IMO no. Is it likely to happen due to your year and mileage, I would suspect so. At your mileage most cars go through a timing chain/belt replacement anyway.
There is a way to check how much stretch you have on your chain by removing the passenger valve cover and scoping the tensioner. You basically count how many "teeth" the tensioner is pushed out. I don't recall the number, but if it's pushed out very far, your tensioner is at max or close to it. This is an indication that your chain has stretched beyond it's useful life and the noise will likely happen sooner or later. There's a good video on Youtube of a guy who removed the cab to do this repair. The first video he shows how to scope the tensioner. He also does the timing chain repair, but only replaces the timing chain and tensioner. I don't really agree with the way he does some of the repair (Pretty sloppy IMO) but there are some good tips in there.