Jack, basically, yes! The US track, when the rubber is completely worn off it, sits on the four corners as these are the thickest part of the steel skeleton. It was this contact that left the little 'footprints' through Dorchester!
It didn't damage the road as such, a Stuart is not really heavy enough.
There is a maximum ground pressure for tracked vehicles on the road in the UK, a Sherman M4A4 on steel chevron is just outside the limit, rubber track is, of course, well inside.