native american arrowhead knife blade knapped Benton? Old? Modern?

Description

I am listing as modern because I do not know how to tell the difference. This came from a recent collection i purchased. It measures approx. 5”x 2”. It appears to be old due to the beveling. Please see photos to make your own judgment. The previous owner states it is authentic but I do not know how to tell. I’ve tried to research but still am unable to tell. It is a beautiful handmade piece either way. Thanks for looking.