Welcome to the forum!

From your description it is not clear what font characters you need (and what they should look like).

- Noteheads?

- Flags?

- Rests?

- Accidentals?

- Clefs?

- Time signatures?

Do you have the November font?

If yes, are the characters you need somewhere in the November font?

Your question is way too vague. There are tons of 3rd party fonts out there including many vintage styles at all sorts of price points and a few are free.

Google is your friend: finale music fonts

Here’s an old list with links to a thousand or so, Not all for Finale:

https://music-fonts.com/ 

You may also need to learn about FAN files

https://usermanuals.finalemusic.com/FinaleMac/Content/Finale/Missing_Font_Annotation_File.htm 

The one by Robert Piéchaud? Not quite what I'm looking for. Thanks for the suggestion, though.

Potentially all of the above features might look sufficiently archaic in what I envision. I'm thinking largely of old typeset (as opposed to expertly engraved) music, with flags that look like truncated, angled beams, and faint but visible voids between the staff lines behind one note and the next, and half-note shapes that are kind of elongated and squashed.

I'm not looking to create beautifully legible scores for this purpose. It's more for display to create an archaic, rough-ish impression to go along with 19th century engravings and woodcuts in a video, while still being readable notation.

I'm getting the impression that what I"m looking for doesn't exist and I'd probably have to create it, which is a bigger chore than I fancy.

Looking through the glyph set, I do see the oblique flags I was thinking of, though.

Ok, now that you've given us some clues, we know that 19th C. fonts are not what you're looking for. You need to go back a couple or three centuries to the work of Petrucci and his contemporaries who created movable type notation fonts. Some of it was still in use in the early 19th C. however, since it worked well for mass distribution such as hymnals. I have some 19th C. hymnals and song books.

I think you're looking for the work of Dr. Ross W Duffin at Case Western Reserve. His fonts go for $50 / set and are designed for use in Finale and work best on Mac computers. Here's where you can find sample pages and contact information:

https://casfaculty.case.edu/ross-duffin/homepage/fonts-for-early-music/ 

Let us know what happens.

GtbrgFIN: https://elbsound.studio/music-font-comparison.php?font=GtbrgFIN

Leipzig 1803: https://elbsound.studio/music-font-comparison.php?font=Leipzig%201803

Capella 1800: https://elbsound.studio/music-font-comparison.php?font=Capella-1800

Capella 1900: https://elbsound.studio/music-font-comparison.php?font=Capella-1900

Classica: https://elbsound.studio/music-font-comparison.php?font=Classica

Also check out the Urtext fonts    (google urtext fonts). They have for example Leizipig 1770 and Leipzig 1803.