Well there are enough similarities between Seinfeld and The Bing Bang Theories that somebody already has compared them.
https://suggestsmagic.wordpress.com/2011/11/28/big-bang-theory-is-a-seinfeld-copycat/
Both George and Leonard share more features that just the looks: they both are obsessive, specially with details, not confident about themselves, they both get frustrated quite fast, had issues keeping steady relationships, even certain body language gestures are quite similar.
But to be honest there is no way to know if someone borrowed George features and characteristics in order to create Leonard, even if the writers were asked because they will never accept it if it was the case.