I think I was neither clear about the issue (my fault!) nor possibly even correct!
On my S7's lock screen, I can see the "T-Mobile" name at the upper left corner of the lockscreen. I thought I remembered seeing this same name in the same location on all "pages" in the launcher app and, since the latest security update, no more. But am I mistaken? I just did a Google search for photos of the S7 and I don't see the carrier name at the top left except in pictures of the lockscreen. All I see in the photos (at the top left of "other than the lock screen") are notification icons. I -do- see all notification icons as expected, though.
I'm thinking this is my first senior moment (although my wife might disagree). What say ye?