Would any of them still have that handset in? even in 1967/68 I would have expected something a bit more modern than that.
Then again the Film is Set in the late 20's early 30's I would suspect from the cars included, so the ancient phone would have to fit in with the period.
There is even a Lancia Lambda (Thanks IMCDB) produced in the 20's and early 30's.

MHV Lancia Lambda 1923 01 [Public domain], by MartinHansV (Own work), from Wikimedia Commons
The Bentley in the film "MG 1280" still on DVLA Database today with a first registration of September 1931.
Depends how pedantic the filmmakers were......the Bentley definitely pushes the "period" for the film into the 30's.
Regards Neil