Roof motor oil is usually golden coloured and thin, only green fluid would be LHM fluid as used on old style Citroen and Rolls Royce suspension systems. Since your fluid is on the drivers side any leaks from the roof hydraulics would be either the pipes that run around the back of the cabin from the pump housed over on the passenger (left) side or the Ram on the side of the leak. Could be someone else has been in there and used LHM fluid, do you know the history of the car, has it had previous owners?
https://www.realoem.com/bmw/en/showparts?id=BT32-EUR-07-2003-E85-BMW-Z4_25i&diagId=54_0313