You're going to get responses all over the place. If you search (and even google) for 'Hemi Tick' you'll get an idea what I'm talking about. My 2013 R/T does it too and did it from day one. It seems to get better, but certainly did not
disappear when I switched to Mobil 1 (synthetic), which I did at 500 miles (I now have over 5,500). The racket also seems to get lower as the car gets older and comes and goes for no apparent reason. It's audible below 2,000-2,500 RPM, while driving, and is RPM-dependent. Too loud for injectors. As for that 'all Hemis' do it line you'll get, my Charger didn't. At all.
Your guess is as good as mine, unfortunately.
Planning to put my mechanic on the case, but I'd rather not do what some did: have the car opened up to replace the lifters and still
get the ticking.