I think you could keep shopping around until someone says "oh yes, you need to do those chains" but really, unless the chains (actually tenstioners) are faulty/worn/damaged then there's little point in doing it.
You're always going to hear a little noise on startup. Injector rattle is not uncommon at all, and the older it gets the worse it gets. At idle, I had a rather bad rattle that I thought might have been my timing chains - it was the side of the airbox that had broken.
It is worth keeping in mind the cost difference between a change to dual-row timing chains vs a full rebuild after a failure, but I think there's a strong air of paranoia created by having a few timing chains let go over the years.
Remember that most people start researching issues on the internet when they experience those issues, so most of the people visiting this forum are here because they've got some issue or other. For each member here, there are 10 "out there" who either don't have the issue (common) or of the few that do have an issue, they don't use the internet to find an answer for it, they just take it to their mechanic.