I did watch maybe a dozen episodes of The Facts of Life back in the 80s, but if the producers hadn't said who Lisa was, I'd never had known it was "Blair." I never really knew the actress's name.
Same with Jeff Kent. Though I remember him playing, I wouldn't recognize his face outside of baseball.
Jim
My DH and I knew exactly who she was. We're in our early to mid-50's and I watched every episode during it's first run. It's not just the age of the show, but the fact that it wasn't shown in syndication the way other shows have been.
Also, there were more than 2 people who knew. Skupin , Denise, Penner, Jeff Kent all knew from what I remember seeing. It was mainly the players under 35 who had no clue.