How can I tell it's Lai Chi Kok Road? The most obvious clue is the corner of the Sham Shui Po police station that can be seen sicking out behind Stack at the end of the row of shophouses in the top two pictures. Until the police went for the current grey/blue paint scheme on the outside of their stations they had a sort of beige/brown thing going on which can be seen in the picture. By the position in the second picture, it looks as though Stack's rickshaw is just passing Kweilin Street.
Actually, this part of Sham Shui Po still has a lot of 60's era buildings and another example is the building on the far left of this third picture. It's the one painted red at the front. It's the Chew Onn building (yup) at 369-367 Lai Chi Kok Road and was built in 1964.
In the next two grabs, the scene has moved down the road a fair distance but there are still buildings that help us identify the exact location. The first one is the distant curved tenement just behind the rear of the bus in the first picture. This building (the Kon Hing Building) still stands at he junction of Lai Chi Kok Road with Nam Cheong Street. But there is also the closer grey building with the blank wall and windows at the end of the bus in the second picture. This is also still around and is at 219-221 Lai Chi Kok Road. It is just next to the junction with Shek Kip Mei Street which puts Stack just around the junction with Wong Chuk Street.