If you like it then buy some more while you can. This is a good ol' case of expression labelling rather than informational labelling.
What I mean by this is that most distilleries state the absolute oldest date they can get away with, as it makes the whisky look more desireable - so it's mainly informational; "this whisky is 12 years old and not a day older"
Some distilleries (Glenfarclas like to do this and Balvenie too) will slap a year on to batch the bottling into an expression of the distillery. So with Balvenie you can pick up a 15 year old Single Barrel which is actually a lot older. I've have a 16 year old and an 18 year old once, both labelled as "15 year olds". You get a lot of old Glenfarclas mixed in with the 15 year old too.
.....The reason behind all my waffle is this;
GlenDronach was mothballed between 1996 and 2002 - it made no distillate. Which basically means that post 2002 Make cannot be **** as 12 Year Old until atleast May 2014.
So that means that the whisky in your bottling of "12 Year Old" is probably a lot older, more likely around 16years - unless they stuck loads of the stuff in holding tanks, which I doubt.
You really want to explore GlenDronach then grab a single cask release when you can, they are stunning.