Do we have any information, insight or even speculation about serialized card distribution, concerning region and types of products?

I was wondering recently about the distribution of serialized cards in the Collector Boosters. In theory, I would expect any Collector Booster I purchase, in any region or language, in a Collector Booster box or coming from a Gift Bundle, to have the same odds of containing a serialized card. Do we actually know if this is the case? I honestly imagine it would also be pretty hard to guarantee this in the factories (especially if they are not all printed in the same place), and I am not sure whether a company would spend more money and go the distance to guarantee a distribution as close to random as possible.

Does anyone have some insight into the printing industry, or these processes? I was curious about this and it's hard to reach conclusions.