I found these three old track clips, two marked "Ives" and an otherwise identical one which also says "Made in U.S. of America / THE LIONEL CORPORATION NY
The end clips match the spacing of ties on Postwar Lionel track, but they have two tabs (at lower edge in photo) that prevent them from being attached. It looks like they were made to attach to an older type of track and from one side of the track, only.
I would be interested to hear any further history or explanation of these items.
I do know the story about Lionel and American Flyer buying out the bankrupt Ives Company in 1928.