Not sure why people are saying this will be like the Fitch fight. Stun Gun has a better top game than Fitch, and is a better grappler overall.
And I am not sure what makes you think Stun Gun is an overall better grappler than Erick. Don't take me wrong, I like both guys and I want to see those two scrambling and as I said, I think is a toss up. But as right now, on paper, I can't understand how Stun Gun is a better grappler. I can give him an advantage in Judo, his specialty, but Erick is a black belt in Judo himself and BJJ. Fighting wise, Stun Gun has only one submission in his career, none in UFC, while Erick has 9.
We shall see after they clash.