Old JW blue label

[TBoner]

So I came across a bottle of this that's at least 10-15 years old (according to the proprietor and the price on it), been sitting on the top shelf of a hole in the wall store the entire time.

$159. I think this is a good price (much better than anywhere else around here).

The problem? It's been on its side. The box is sealed, and I had no money to buy it, so I didn't really examine it. Anyone know if this was a corked bottling at the time? I'm afraid it will have been damaged/tainted by being stored on its side. The proprietor said it was there when she bought the place, and she doesn't know if it was stored that way the whole time.

Thoughts?