Protein structure prediction has been done for ages...
... now there is money for AI, so it is done with AI. Usually, those algorithms are informed by (learning? Lets make that extra-deep learning to make sure the funding comes through!) and run against known structure to test how well they perform. So it's not like there weren't any yardstick they could use to compare the expected quality of their structure to those of other modeling efforts. Unfortunately, even 98% or 99% correct predictions can be completely worthless, imagine taking just one wrong turn when driving somewhere.
Even if they get the structure of some virus proteins right, that does not give a vaccine. I'd expect that they already plenty of lot of known proteins that are shared between the new virus and other known Coronavirus strains. So yes, it sounds very much like a PR stunt. Made it into the Register through, so it was a good one!