Buick During The 1920's (A short film).

This short film shows the chassis line, body drop, radiator department, top department and ends with the "Unified Assembly line". Judging by the radiator surround, I would place this as 1926-1927. This link shows the steam booth that is at the end of this film:

Factory #62 Revisited.                                                                                                                                                                                                                                                                                                                            I wish I had a copy of this film.