Balvenie single barrel distilled date?

hi all.  Was looking to see if anyone knows how to tell what date (year) a bottle of the Balvenie 12 yo single barrel was distilled and/or bottled in.  I watched a review that was a few years old and noticed that my cask number i just purchased was quite a bit lower,  then saw another with a much lower cask number from not too long ago.  So... do cask numbers have anything to do with dates, or is it all random?  Also, I think with Springbank, you can find the date via the %ABV.  Any chance Balvenie does this?

Thanks a million!