I'm glad I found this post. I was just given some really old bottles of Johnny Walker Red and Black, as well as some Tanqueray.
Can I email in pix to see how old they might be? The bottles are sealed in what appears to be a holiday gift box.
I just cracked one of the Black bottles open and tasted against a bottle I have that's a few months old. Seemed to taste the same, so far, but I only had a sip.