Of course ! (But notice, that I said educated people know him. By educated I mean those, who listened in school :) ) .
Lem has ,,his own two shelves" in every bookstore that sells SF, we have his books analyzed in elementary schools (I mean few of his stories, like ,,Mortal Engines''). Every SF fan knows Lem, at least those who read books (by this I mean that, sadly, there are SF fans who limit theirselves to watching movies and playing RPG and stuff...).
Besides, Lem is a known personality, very respected due to his age, experience and... high IQ (his is considered one of the wisest Poles, as his IQ is something about 6789... or some ;] ).