I suppose it's less surprising to see Junior make a cameo on his Dad's card than that of anyone else in the set, but the definition still applies.
Looks like Junior may have done something gold glove-worthy on the field, and his dad is giving him a "good hustle" tap. We also see Senior in what would eventually become Junior's number when he moves to his hometown Reds a decade later. And not to sound weird, but Ken, Sr. has some nice eyelashes in this picture. Overall, this is a great photo of the father-son pair in the short time they wore the same uniform.
There is a disparity among holograms in the 1991 Upper Deck base set. I don't appear to have any of the variations to show you, but you can read about them here. As a completist I would list them as collection needs, but that is a level of anal I just don't want to touch.
There were few really great sets in 1991, but Upper Deck made it happen. The cherry on top was their 100-card Final Edition set. Tune in tomorrow for that bit of tightness.