There are many sheet issued stamps which were used to create the makeshift booklets. These used regular sheets of stamps and once removed from the makeshift booklet are unidentifiable as such.
Here's a few examples from my collection:
The first 3 you pictured were not made from sheet stamp stock, they were made from booklet pane stock that was cut differently than used for normal booklet panes, and as such the MDI panes can be identified as coming from a makeshift booklet.
Michigan Dyslexia Institute, Inc. (MDI)
Nope, MDI stands for Minnesota Diversified Industries.