Supposedly he did strongly hint at it in one of the "History of Marvel" magazines they used to put out back in the day. But even if he didn't, there's still plenty he has taken credit for, almost all of which his main contribution was the name:
Spider-Man (Ditko)
Fantastic Four (Kirby)
Doctor Strange (Ditko)
Avengers (Hulk, Thor, Iron Man, Ant Man, Wasp) (Kirby)
X-Men (Kirby)
Lee's greatest gift and talent is that of a salesman and he was once upon a time a great ambassador and promotor of comics. The problem is, he was just as much of a salesman and promoter when it comes to his own legacy, and it's road paved with bull ****.