I should have connected the dots a little better on that Station to Station item: The finished album, as I mentioned, ended up with only six tracks, but David Bowie recorded some other material around that same time, including a cover of Springsteen's "It's Hard to Be a Saint in the City." (That particular recording is available on the Sound + Vision box set.) So Bowie had been a Springsteen fan from the early days, and may have been impressed with the piano playing on Bruce's first records.
Except, of course, it was the great David Sancious tickling the ivories on those forst two Springsteen albums, and not Roy Bittan. But as messed up as Bowie was in those days, I can easily believe he wouldn't know the difference.