Mano ?

I've been wondering if the object in this next set of pics is a mano. For those of you that don't know what a mano is...

"Manos refer to the handstones used in conjunction with milling basins and metates for grinding seeds or grains into flour. They are common artifacts on many archaeological sites throughout Oklahoma. They were utilized over several thousand years, earlier for grinding wild plant products and later for grinding maize (corn)."

In other words you take a big stone, throw down something that needs grinding, take a smaller stone in your hand and start grinding.

The only reason I think the stone in the pics below might(?) be a mano is that the edges look ground down to me. They've been smoothed.

Anybody out there with knowledge of this stuff agree with me? Let me know.

This first pic is the end that is obviously broken.

Here are two pics that show the wear and tear of grinding.

I'll keep searching for the larger grinding stone called a metate. It's gotta be around there somewhere.