Like most things in the Cooper case, nothing is certain,, the tide range is about 1.5 - 2.5 ft.. the water level looks very close in those images.
It is clear the shoreline at the money find spot changed between 1971 and 1973, a dredge/beach replacement is most likely but not confirmed. There was also the '72 flood.
Whatever it was, there was a change in the shore at the money spot between 71 and 73..
Here is a higher water level in 1970,, no undulations in the shoreline.