KMB #94 to Sai Kung?
Haiphong Road is quite easy to recognise due to the shading banyans on the north side of the road (where Rosie Rowell, who plays Donna, is standing) along with the old wall that marks the southern boundary of what was Whitfield Barracks but is now more commonly known as Kowloon Park.
Perhaps the bus sign was a spare that the local production company had lying around? Or perhaps in 1992, the bus did actually go this far? I can't comment on the latter because it is before my time but I suspect the more likely reason is the former.
Anyway, never mind. Here is the modern Streetview grabs for comparison. The white building at the background of the first picture is the Kowloon Centre over on Ashley Road.