Discussion about laser scanned tracks in any game is gone ridiculous. Why we need 1mm accuracy? Many gamers not even notice if accuracy is between 10-50m.
OK just joking. But actually not joking

If for example we'd take Nordschleife with 100% accuracy laser lidar nano-accuracy scanned, but then increase it's scale by 0.0024% its overall length would increase by 50 meters, and I guarantee no one would notice without measuring it.
In my personal opinion there are critical parts of tracks such as apexes, cambers and humps that are super important to get right, I suppose in relative accuracy (relatively to objects in ~30-50meters radius) it should be possible to eyeball stuff within 20-40cm accuracy even by just referencing to aearial pictures such as like those from Google Earth and pictures + videos.
If you have used some data that is 1-5cm accurate, I guess it is fair to say that your end result must have been more accurate than that. If I understand LiDAR, the error that is specified for the pointcloud must be meant for individual points. And the more dense the cloud is going to be in given area, the better errors will cancel each other out, and after smoothing the actual error for surface should be very low.
Another aspect is the accuracy of features. I'd suppose, that will depend on the execution, the way point cloud is going to be used. I think it is fair to say that Nordschleife of Kunos and S397 are completely same, and completely different at the same time. All the differences are in the features of road, Kunos Nords seems smoother, has less pronounced undulations. The Nords of S397 is a lot more rich in road features. For example these two are very aparent in S397 version:
The "double top" of Shwedenkreuz, the bump right after the top of the hill, it is well pronounced in rF2. You can see it very well in this video at 0:38
The dip at 1:19 in this video never felt right in AC to me, but it could also be related to aero, front height sensitivity and similar stuff that would take part in unloadign the car or even lifting it up from the tarmac at undulation like this. This also tells that car physics working together with track model has an impact of perception of a track. Laserscanned car physics when ?