I'm going to say "no", but not because of the Dev Center issues.
Last time around WSJ confirmed the release of B3 a few days ahead. So far, we've heard nothing about B4. It seems strange that someone would tip them on B3, but not B4. For that reason, I'm figuring the 29th.
I don't think they're going to wait until the 29th. I think as soon as they can get this mess straightened out and the Dev Center comes back online we should see beta 4 shortly after.
Unless of course, there was no beta 4 schedule for today and they're doing longer intervals between betas as we approach the fall.