That's a tricky one because he has a very ...... "Mike Love" way of expressing himself ..... He's certainly expressed sorrow over things, people, events ...... But a public "I am sorry that I contributed to SMILE's demise" from him? ....... Never gonna happen. And if anything like it does, it will require quite a bit of reading between the lines.
I honestly wonder what Mike would do if he had access to time travel.
Getcha Back to the Future, anyone?