In 1976, my older sister took me to one of the conventions at NBC plaza in NYC for my 9th birthday. (We lived nearby in Long Island.) I was pretty overwhelmed and too young to fully appreciate the whole event, but one thing I remember clearly is that the first actor to speak was Mark Lenard. He was as classy, sophisticated and enthusiastic a participant as you would hope for, and I appreciated Sarek and General Urko much more for having seen him. I was glad he was able to reprise the role and give it finality in TNG.
I still have the program from that event, and Mark Lenard is clearly featured in the photographs.