As far as clients go, they can detect you are using software, they can't go as far as to detect exactly what client you are using. And as far as ive been told/heard about detection systems, mouse movement is small part or how they go about detecting bots. Other factors possibly include run time, botting hotspots, age of account, flagged IP's, similar names of bot accounts.
Its pretty hard to replicate both humanlike mouse movements and botlike movements, there isnt really a way to decern which is which in my opinion. I do some weird ass mouse movements that other people don't, I click on random tabs for giggles, I examine stuff but dont read any of it.
So in an honest opinion, I highly doubt OSBot's or any other bots mouse movement is massively detected due to the fact its hard to replicate both sides.