I have a feeling these are produced on an actual typewriter and using actual stencils respectively. Slight imperfections, bleed, differences in the same letter at different sizes...

You could be right for the stencil font because on a lot of photos you can see that they used real stencils. As you said, imperfections and »bad kerning«. But in the book for their 20th anniversary you can see that the font is set digitally (it could also be a custom font, of course). And for the typewriter I think the letters are pretty much the same, take a look at the a and the g for example. This one is definitely digital.

I'm looking at the /a/ and /g/ and I still say likely typewriter. It's not hand-lettering, of course the lettershapes are roughly the same, but look at the bowl of the two /g/s, the lower portion of which is noticably differently thick. For the /a/s, the very first /a/ has been struck lighter than the rest, the second and third heavier.

Have you got a sample of the anniversary book text?

I wrote to them yesterday and got an answer. The typewriter font is definitely Trixie Plain. This fits because they generally use system fonts for everything.

They still didn’t say anything about the stencils, though.