I don't think you're out of the woods yet. I really feel I have to be honest about this after seeing the photo of the rivet -- it looks completely wrong to me. I already mentioned that the bale doesn't look right. Have you compared the bale side by side a known authentic bag's bale? It doesn't appear to have the "curves" or "dips" that an authentic bale has. Please take a more "straight on" photo of the bale - it may be easier for us to see the exact shape of it that way.
BTW, as far as I know, there have been no known sightings of authentic Firsts with leather tag & brass hardware. Leather tag & silver hardware, yes, but leather tag & brass hardware, no. Please someone, correct me if you know of another case.
Unfortunately, Sales Associates, no matter how long they've been selling, aren't necessarily the best authenticators.
BTW, as far as I know, there have been no known sightings of authentic Firsts with leather tag & brass hardware. Leather tag & silver hardware, yes, but leather tag & brass hardware, no. Please someone, correct me if you know of another case.
Unfortunately, Sales Associates, no matter how long they've been selling, aren't necessarily the best authenticators.