Just thinking out loud here. Would putting a pre filter such as a cyclone type , on the OEM raised air intake just cause more air to be sucked in through the unsealed parts of the air filter system ? So defeating the object if you don’t have a sealed system.
The theory checks out. The pressure drop would increase ever so slightly between the RAI head and the air filter due to the precleaner acting as a restriction. Some 'dirty' air could get pulled in through the inlet duct gaps. About this much maybe?
Most would still pass through the precleaner as the path of least resistance and all of it goes across the airbox panel filter.