Glenrothes Distilling and Bottling Date Confusion

I'd appreciate if someone could educate me on this...

I bought one of those triage box sets. However, I can't find the exact products/vintages on-line. The Glenrothes website lists ones that are close, but not the same. What differs is the bottling dates.

The box includes the following...

Distilled 1991, Bottled 2007
Distilled 1987, Bottled 2006
And the Select Reserve

The site liste both the '91 and '87 but with labels showing them bottled in '08 and '04 respectively.

By using my newbie logic I'd determine I had both a 16 and 19 year old scotch! Ergo this couldn't be the same product as listed. What I need to know is if this an incorrect way of determining the actual age.

So the question is.. just what did I buy? And where can I find more information on those vintages that seem to be unlisted? If only Glenrothes labeled their bottles by age in the first place...

And in case anyone is wondering...

The '91 is fire! I could not tell you what it tastes like if my life counted on it. But I'll work on the bottle and see if I can improve my discernation... I opened the '87 thinking I would be just as dissapointed, that all whiskey or Glenrothes would be just as tough, and that I just didn't have the taste buds for it, having burned them all off on intensely black french press coffee over the years... I was deppressed thinking that that was the case, that I'd never become a conniseur[sp].

Was I wrong indeed! For the record I recently had my 21st and this had been my first taste of scotch (after the '91), and I must say the '87 makes me feel like an undeserving bastard! What I mean to say ladies and gentlemen, is that I find personaly find this an excellent scotch, but for an ametuer to say that, is I suppose like losing your virginity and thinking that its the best sex you ever had when its been the only.

As soon as the first swirl of the '87 collides with my tounge, immeaditely it conjurs up the memory as a child of putting my finger into a fin john of fine imported melted Irish butter on the stove and licking it off.

No, not the taste of butterscotch, but of butter! Soon it turns into a floral vanilla as it slides down my greedy gullet. All that I know is that nothing, not even candy should taste this good. Don't mean to drivvle on about it, but I simply had to share my first (and most unforgettable) experience!