The original model and works very well for it's intended purpose. As I was planning on printing it I decided to do some small improvements that made my life easier.
The covers and spine now have 1.8mm holes, as do the pins. The idea is to use piece of filament to lock the pins in place. I used soldering iron to ‘weld’ the filament in place. Use a 1.8-2mm drill bit to open the holes if the filament doesn't fit.
The pin holes in the covers have been remodeled such way that the hole overhangs should print cleaner.
Pins are now in separate models. Print following:
Use 12mm M3 screws to install the rest arms.
Some custom support models added, see if they work for you (spine, rest-pin).
OpenSCAD source here: https://github.com/spegelius/3DModels/tree/master/Foldable_Book_Stand_remix
The author remixed this model.