My grandfather met Mr. Griffith in the late 60s or early 70s
It's funny you mention your grandfather having met Andy.
My granddad, still alive and kicking at 90, has this irrational yet burning hatred of Andy Griffith. Whenever he sees him on tv, he shouts, "That is the meanest god damn man that ever lived!!!"
Once I asked him why he hated Andy so much. The reason is that some old fool that my granddad drinks beer with swears that Andy Griffith cheated him on some business deal fifty years ago.
This same guy also swears that Elvis Presley stole one of his guitars.