I've seen full page ads for computers, only to be followed up months later with an apology that it's been cancelled. I'd use dates on ads as a guide only, not as gospel.
I know and I am still reseaching for adds and annocements (Press Relese). I just Seen a YouTube video for AT&T 3B2/400 said date 1983.
401 errors for the dropbox preview links.
So what is the best hosting for images, and PDF files on this forum??? I will improve this, Later..