That might have been the case decades ago. For example, in the USSR, various finger gestures usually implied something related to a penis and were considered extremely offensive. But that hasn't been the case since at least the early 1990s, when VCRs became widely available, people saw Hollywood movies for the first time and got used to westernized meaning of thumbs-up and OK gestures. Nowadays, when backing a truck towards a trailer, a thumbs-up would be taken as "good job" and an OK gesture (often paired with a kiss) as "exceptionally well done".