Are you hearing about their bullishness from him or them? And are they prominent investors, or noobs?
From him. Yes they are prominent.
The company isn't a YC company. But the investors ar quite prominent people.
Are they profitable? Or do they have tons of users? Founders that learn to hack and create something people want are quite formidable people. Even if they take a step back into financing, hiring, and other CEO functions after more experienced hackers come in.