Here's a great example of a missed location. It's the section of Lung Cheung Road that runs past the north end of Kowloon Tong.
This part of Kowloon hasn't really changed at all and all the buildings you can see on screen are still there and fairly unchanged. The main building in the top picture, alongside the road, is Pearl Court. Built around 1966 it's one of the older buildings in this area but not by much as most of this estate was completed by around 1970. Compared to today's shoebox flats these older buildings had much higher ceilings and more space and tend to still go for a tidy sum.
Far right of picture two is the edge of Beverly Heights, a name that should be familiar with Bruce Lee fans because it's where he died about 2 years after this film was made. The yellow podium next to it belongs to Chermain Heights which sits on the opposite side of Beacon Hill Road.
The playground (called Lung Cheung Playground) is also still there but now the view is interrupted by sound barriers and tree growth.