Ken Grunke writes:

Production units are probably cut with an internal broach.

Here are some photos of an 8-tooth 16mm film sprocket (3/4" diameter)

http://www.truetex.com/16mmsc8.jpg
http://www.truetex.com/16mmsc9.jpg

The streaks on the surfaces of the tooth wheel sure look like it was milled
in bulk axially, then sliced off, maybe ground?