This is correct. Depending on the emulsion, grain is also not sized uniformly.
And since you posted the Take 2 Films' tour of Kodak, it's also worth pointing out their latest film is comparing a couple of different film stocks and methods of processing them. This aligns with something that I frequently say - "film look" is meaningless as a phrase, given that different films have different characteristics - and depending on processing, can take on even more other characteristics.