https://docdro.id/SQ5B74V

"One of the surprises was the discovery of gas bubbles in a copper spear head/point from the Osceola site. This porosity was identical casting bubbles found in some of OMC's cast aluminum engine blocks."
"Unlike other copper points, which show a hammer-only mode of manufacture (solid body with occasional oblong voids), this point was filled with porosity from gas bubbles; evidence of casting."
"The appearance of two sets of multiple, parallel, striations, on opposite sides of the same end of the Osceola awl, suggest that the artifact was cast, allowed to harden in the mold and lightly finished (hammered, polished) thus preserving the flow lines which, otherwise, could have been easily flattened or smoothed away."

There must be more of this on the mississipian valley sites. I guess it's only a matter of time a lot of those tools get studied intensively.