I also remember such episodes from my days at Intel. I worked for years on embedded controllers and we were always trying to wring those last drops of performance from older processes for embedded designs. You could, indeed, have a point!
It was a Huge amount of labor and tool downtime, and even then, the Bin-1 (Highest Speed) Yields were..... less than desireable. Pure speculation of course, but I wonder if the same thing is happening at AMD?
My take is that there aren't any bin1s or likely 2s or 3s.