Copyright on Transparencies

Hi Everyone.

I have recently purchased transparencies online... mainly vintage
images of cities, New York, San Francisco and other places.

The slides are mounted in Kodak frames while others are blank.

There are no markings to suggest they were produced for a newspaper
or photographic company... they seem generic and executed by
unknown an photographer(s)?

My question is can I print the images and sell them legally?

If you can help that would be appreciated?

Thank you