The first photograph is mostly likely from the mid-1960's. The second looks more like 72-73.
The photographs are a matt finish.
They look as if they could have been printed at the same time.
The listing called the cards "RPPC". That stands for "real photo postcard". This means that the image is developed onto postcard sized paper with with a postcard back. The Kodak backs date from 1950-present.
That's about all I know. Any additional information would be appreciated. Do you have any of these? Seen others? Common? Rare?
Below with a little help from Picassa