I would agree 100% with Gary here, and I would go a little further and add -- with examples I can taste right now -- that, of all the brands Beam obtained when they purcased the National Distillers' assets, they have treated Old Grand Dad with an admirable amount of respect. That wasn't true of Old Crow, which they gutted -- I believe quite intetionally, since it was their major competitor before the purchase -- or Old Taylor, which they did "downgrade", but only gently and slowly. .
Old Grand Dad, on the other hand, has always been treated with respect.
Perhaps that's because the Old Grand Dad distillery at Forks-of-the-Elkhorn (near Frankfort) has now become Beam's main aging and bottling plant. I don't know -- Old Grand Dad (AFAIK) is now distilled at Beam's Boston distillery and then trucked to Frankfort for aging and bottling. In fact, it might not even age there; I'm not sure. All I know is that we have samples of OGD from several decades (unfortunately none before National Distillers -- anyone out there got any pre-pro samples? P.M. me... PLEASE) and I have to say that, of all the different brands that have changed ownership in the past fifty years, Old Grand Dad is (along with Old Overholt -- also a Beam-owned label) the one LEAST different from the way it used to taste when made by it's original producer.