Nope. It would just cause more deaths. If HK citizens are armed, China will just show up with its army and navy there. China's navy can hold its ground against its neighbors(Vietnam, Philippines, Indonesia, ROC), HK will never be a problem to them if CCP orders them to level it. I'm not even going to start talking about PLA.
Also, the argument that an armed civilian is better because it makes the government wary does not hold out in the current time and history. A government has the resources of the whole nation, while the population does not. I don't know how come Americans believe that they can hold out against its army when its army is able to fight wars on numerous fronts. There are so many guns in the US because of its constitution, not because it can actually protect against the government. The myth of protection is just propagated by pro-guns who also believe in it.
Right now, the best way for HK citizens is to migrate to other countries. If China continues to be like this in the coming years, there is no way that HK will be the same in 10 years.