I suspect that adding "knicks" were an option left to the leatherworkers discretion when completing the foldover that's part of this tab receiver design (for when the die cutter left the edge of the tab that's to be folded under too far up the corner radius of the slot). I've a metal tag courier in mocha that shows some minor razoring in a similar location.
Regarding your "decade apart" in age estimate, I suspect that may be an exaggeration. From what I've seen, COACH metal tags were employed on pre-creed bags till 1972 or so, That method of identification was then superseded by cartouche imprints (or riveted leather cartouche tags on those styles where a "good" location for an imprint could not be identified) till the introduction of creeds in 1974 or so. So in all likelihood, your two pre-creed large courier pouches are within a few years of each other and closing in on 50-yo. Great bags and I trust that they will serve you well for many years to come.
That's great info, thank you! I've got a lot to learn about these older bags yet, that's why I'm here! I guessed the age of the bags as around mid 60's for the metal tag and around mid 70's for the cartouche but that of course could be way off. It doesn't matter to me, I'm just so thrilled to have a little piece of Coach history.
