The fact that they've done this for multiple other products built on FOSS projects is a pretty good indicator it can happen.

Aurora is a good example that's explicitly marketed that it's a different core storage engine, but they definitely make many modifications to the projects they're building on top of, but what kinds of changes really varies.

They're certainly capable of it but I believe they would talk about and differentiate it more explicitly if they had any Aurora-like special sauce.