They gave it another go, but on a shorter track this time. Even with that, I find it hard to believe they'll back up their original numbers had the track been as long as the original run.
They will be able to do it. Starting speed doesn't matter that much.
A Chiron that ran there appears to have used far less of the track and still hit 260 (example, Chiron was doing 80mph at the same spot the SSC was doing 130mph.