In short: Yes. It is a polite way to acknowledge an enjoyable game.
"Good game" isn't the same thing as saying, "well-played game".
Saying "good game" just means you enjoyed playing it. You could have enjoyed it for many reasons. For example, it could mean something as simple as, "thank you for being polite and not stalling or offering draws from badly losing positions", or "not being a d*** when you lost".
It could even mean, "yes, I clearly won, but you kept me on my toes".
"Good game" does not imply that the opponent played well in any way, and is the normal polite way of thanking a person for their time. If the person is rude to you, or obnoxious, then you wouldn't probably feel the desire to say "good game", no matter how well they played.