[Dixielandjazz] Question re Tommy Dorsey Stereo Film Clip

[Fr M J (Mike) Logsdon]

Please forgive my ignorance, but I'm uncertain about something.  The 
1943 film was, of course, in mono.  But when was the stereo track 
recorded?  1943?  If not, how was a stereo track so many years later so 
perfectly matched to a 1943 film (solos, tempo, etc)?,
-- 
Etc,

Fr M J "Mike" Logsdon
Special Assistant to the Presiding Archbishop
North American Old Roman Catholic Church (Utrecht Succession)
www.naorc.org