Probably not - left it too late to book a train down and couldn't find a bike space when I checked the other day (couldn't make up my mind between RttS and a local audax on the Saturday, and I'm not really hardcore enough to do both).
I did the first one (2015), though, and it was a good ride. It's a nice easy route - prevailing tailwind and pretty much flat. The group I was with managed to miss the sun by setting off far too early and finishing while it was still pretty dark, so I'd recommend not doing that (did mean we got to the chip shop in Moffat before the crowds, however!).