When abs is fully locked it will scuff the road as the tire is locking up and releasing very rapidly but it is still spinning almost as fast as your actual speed. If you look at the mark it’s just a wash of the surface and may have a light dark tint to the mark or even a white tint (wash) to the road surface. A tire squeal and solid black mark is the actual melting of rubber from friction which you should not have gotten for more than a fraction of a second. If it was a dark solid mark I would think it’s not working and it probably would have wanted to kick out if locked up.