Since these engines have a tensioner for the timing chain, is it fair to guess that it compensates for slack in a worn chain and that even with high mile engines, the cam timing stays true?

The cam timing will stay slightly closer with a tensioner but nothing is as precise as gear drives. The GEN 3 or Gen 3.1 hemi chains and tensioners don't seem to really wear out much up to at least 300,000 in my experience unless the engine was not serviced properly or ran hot multiple times. The tensioner is there mostly for noise purposes not performance. With a roller cam and steel gears the chain won't stretch much because the roller cam is much easier to turn than an old flat tappet/plastic gear combo.

Even on an old worn out and sloppy LA or BB timing chain I don't think it could change more than a couple degrees unless it is bad enough to jump a tooth.

Are you familiar with this?

February 2014
Dealer Service Instructions for:
Customer Satisfaction Notification P01
Engine Timing Chain and Chain Guide
2009-2012 (LC) Dodge Challenger
(LD) Dodge Charger
(LX) Chrysler 300

https://testing-public.carmd.com/Tsb/Download/102061/000000003b9b3c29

That covers 3803 of the millions of vehicles produced.

Uh? 2009 through 2012 Chargers, Challengers and 300's equipped with 5.7.

I got free replacement of my Timing Chain and Tensioner under this despite having no issues. 2010 Charger Pursuit. Thought I'd let him know in case he has any of the above models. Seems he has a something with a 5.7 so might be able to get a free chain and tensioner.

A new timing chain on a 360,000 mile engine is like a boob job on an 85 year old woman!

Ohhhh, stop getting me all worked up with that analogy.

What if it's a freebie though?