Wedge implies asian origin.
The "lug" edge is distinctive, as are the seat for the quill bolt head, and the diameter change just below the extension.
The font resembles those used for ephemera from early aisan imports, late 50s or 1960s.
Is there a hole at the back of the extension?

It's been polished, the lug edge is blurred, as is the diameter change, and (at least) two spots on the bar clamp have been flatted.