Not an answer Mick but a little related anecdote.
About 6 years ago - when I had the store / studio a lady brought in a great B&W portrait of her grandfather and asked about reframing it. I looked and said it was very reminiscent of some Ansel Adams portraiture I'd seen - particularly some he'd done in Rochester, NY. Turned out that her grandfather had worked in Rochester so I told her that an AA portrait would have an AA Photography sticker on the back of the print; but it would have to come out of the frame to check it. We opened the frame and, sure enough, it was an AA original!
I'm sure the sticker wasn't archival in any way - the inks, the paper, the adhesive - but the print was pristine. I was chuffed, 'cos the customer was well impressed that recognized the photographer from a print of Grandad!
Maybe the paper from the sticker acted as a barrier - but then I would think that the adhesive would be a greater risk. I haven't seen archival stamp pad ink available. Could you ink a virgin stamp pad with india ink - that's been used a lot for spotting in the past.
Interesting question - hadn't thought about it that much, but like a lot of other things, I probably should have.
Bob H