Thanks again for the info B.Diddy. I will do as you suggest, (although my un-intuitive so-called auto-replace Samsung keyboard just tried to say: 'I will so as you digest'
Sorry for delay in replying; this last week has been a bit hectic as my notebook motherboard-to-video card coprocessor connection burned/or I guess finally cooked-out last Thursday, the 23rd, (although after 10 years of constant business use). So, a few hours after backing up with Smart Switch to PC, I lost the computer !

Then new S7A arrived Friday afternoon, so I downld'd Smart Switch to the (AT&T store S7A) I had decided to return and took both to local AT&T store. Didn't have to use SS though, as they used their quicker data transfer machine.
They did charge $45 for re-stock, but offered same insurance for the Amazon unlocked S7A, which came loaded with 6.0 (instead of 7.0 like store S7A).
At first I was bummed....but by Sunday had decided I like Marshmellow better than Nougat.
So that's it. New (amazon) S7A running same/as well as (store returned) S7A. Thanks again!
Now I'm wondering about the 2016 S7A recall. How to determine if an S7A is a: pre-recall, or post-recall S7A?
Update: Found date of manufacture + all other info re phone on 'Samsung Info app'