Charles. Both tires are stated as having essentially the same tread depth remaining (8/32")
Isn't 10/32 or 11/32 new tire depth? If so, then it would be reasonable to say that the tires were used in different environments and wore differently. Could be a lot of factors that change the appearance of a near 50 year old tire...
In my humble opinion, the tread pattern looks exactly the same, one is showing a more smooth wear pattern than the other.
Attached is a pic of an NOS tire, still has the nubs on the tread.