What are these markings ? (2017 ram)

The plugs on my 340K mile 2015 5.7 Hemi were the originals when I had a valve get stuck. The tech who diagnosed it asked me if I ever changed them, they still looked good!
I sure hope its not a valve train issue

But shes going in on Wednesday for plugs and coils, im leaving Thursday for a small vacation, so IF the heads need to come off they got a week to do it