Not that silly really, well maybe a little...
As far as i know it won't "go off" but it definantly is not getting any better. After it is taken from the casks it should be at it's best and likewise should be drank straight away with thoughtless abandon (comes natural for me lol). As for the question is it a collectors whiskey i don't know but google will. *goes away to google* Ok im back it retails for around the $65-$70 mark and is currently in stock at the online shop i just visited.
Heres a tidbit---
Macallan (12 yr., 43%) 93 A seamless whisky of great integrity! Full amber color. A rich, fragrant aroma fills the nose with honeyed sherry, smoke, and light fruit. Its flavor delivers what the aroma promised, with a very full, voluptuous, balance of sherry, caramel malt, delicate fruit and smoke. A beautiful, full-bodied, sherried Speyside.
My guess is that it isn't a collectors dream, so get to drankin!!