Lewis had lent his name to a series of videos called Grampa's Silly Scaries, Grampa's Monster Movies and Grampa's Sci-Fi Hits which were collections of cartoons and live-action sci-fi and monster movie clips from the 1930's to the 1960's that featured introductions and commentary from Lewis. (I assume that the videos' producers called him "Grampa" rather than "Grandpa" to avoid tempting a lawsuit from the producers of The Munsters.) Lewis's agreement with Amvest Video, the company that produced the videos, apparently required him to promote the videos with personal appearances in malls and stores like the one I worked in. We didn't get many "celebrities" (even D-listers like Al Lewis) in my store, and since I had enjoyed The Munsters as a kid I thought it would be kind of cool to get his autograph. I wasn't interested in buying any of the videos, but his promotional people provided photocopied pictures that Lewis was willing to sign.
To this day, whenever I stumble upon a rerun of The Munsters, I can't help thinking back to the time when poor little Billy was traumatized by "Grandpa" Al Lewis.
(Above: One of my most prized possessions–my autographed picture of Al Lewis.)