Is it known if Bob Dylan ever met Roger McGuinn?

They sure did! Many times.

If you want proof look at the first pic in the link

*Edit: I was looking through some of my books on Dylan. They met early on when the Byrds released thier Tambourine Man album and then when the Byrds broke up McGuinn even toured with Dylan in 1975/6. They kept in contact and he opened for Dylan in 1987.

Yes, Robert Zimmerman met Jim McGuinn. Probably met David Crosby too.

Certainly, and the Byrds helped popularize Dylan, along with Peter, Paul and Mary. They were part of the same folk music scene and crossed paths often. McGuinn changed a phrase in one of Dylan's songs without permission, so when Dylan recorded it he sang it the right way with a twist:

Pick up your money and pack up your tent, McGuinn, You ain't going nowhere.

McGuinn got the zinger and the message, and related the story ever afterward with a certain pride.