Checking for tiny inaccuracies to detect forged documents is a pretty common phenomenon. Soviet counterintelligence had it down to an art. Forged documents confiscated from captured spies were analyzed for more signs to be used in the future.
"Party membership booklet: bright red cover with barely noticeable stripes. Rough and blurry font. The staples are made from stainless steel. The photo is printed on glossy paper."
"Inventory book: bright blue cover with a satin sheen. On page 3 item 1 the letters мен are missing in the word наименование. In the word книжка on page 3 the letter ж is capitalized and the first и in the word описания has a rightward stroke that continues downwards as a comma. On page 7 the letter и in the word описание looks like a п. On page 8 in the word свитер the letter в is replaced with a German "V". On page 15 the word описания has a dot above the и and я."
Via hranitel-slov.