That's cool! Shun made a pretty explicit point of not telling anyone Dave's shit and nothing at all good came of the situation where that happened anyway, so honestly once he establishes it's a different Dave he'd more than likely not bring it up at all - hell, I could have him lose the memories that were exchanged in a canon update or something. Of course, if you'd prefer to avoid CR with Shun altogether regardless of that, that's cool too.