In the first picture they are parading for inspection, guns do not HAVE to be worn.
In the second picture you cannot tell if they are wearing guns from that angle. Prior to the mid to late 80's guns were worn on the left in a cross draw holster.
In the third picture you have Chief Inspector Rod Mason as a Chief Inspector and company 2 i/c in a PTU Company. The multi coloured lanyard is a Commissioner's Commendation for some brave work cracking a drug smuggling syndicate as an undercover officer. The caption is wrong as he joined the HK Police around 1983. He has sadly passed away recently; so please be careful with what you say about him.
Prior to WWII the HK Police were armed.
Post WWII the HK Police carried -
Webley (first issued in 1930's)
Colt Police Positive
S&W Model 10
S&W Heavy Barrel Model 10
Uniformed officers on patrol have been armed in HK longer than you have been alive.