That's lettering, not a font.

Any idea what resembles it? It looks like a mix between Pauline and Cocktail Script

It also resembles Apricot. Could this be it?

Every style by every lettering artist had/has its own idiosyncrasies, and very few of these myriad personal styles were/have been turned into fonts.

And the lettering artists would also modify their styles all the time, they weren't robots.

So it's probably better to narrow down your selection to a few fonts that are close in feeling, and choose the one that best fits the particular project you are working on, considering, for instance, the issues of x-height and line-breaks as they relate to the copy you have to work with in the document format.

But if you are really in love with this particular lettering, why not digitize it? The "Speedball" style is quite easy to render—draw a path and stroke it.

>That's lettering, not a font.

respectively not. it was a film font. I do not think it's been revived.

it was a film font.

Would a film font have had so many alternates? Compare all the t's here.

I'm presuming you were referring to this opening text David, and not some later titles.

Justin, photolettering could have one or more alternates for any given character in the days of hand-assembled or handset phototype.

True, but those variants were to handle different letter combinations, not to give typography the irregular look of hand lettering.
That idea belongs to the OpenType era.

Film type didn't exist in 1940, the date of the film, did it?

http://stbride.org/friends/conference/hiddentypography/phototype.html