I'm a fan of FJ's publications. For more info about him and his works, check out my Trekplace web site (trekplace.com).
The blueprints and technical manual were created by hand. The reason much of the callout text looks handwritten is because it was-- using stencils. The dotted portions of the drawings were made by cutting shapes from pre-printed material and applying them to the drawings. To my knowledge all of the artwork was drawn at the size at which it was printed.
I have seen some of the original artwork in person, and it's crazy cool!
Exactly. When you take into account that he did it all without a computer, and he was inventing from scratch the then-unheard-of genre of sci-fi technical drawings for public consumption, his stuff is all the more impressive.