Many thanks for your kind comments!
Paul, yes, this is a Japanese Navy PT boat.
Dan, like many other warships from Mini Hobby, this is a copy-cat of Tamiya's PT-815 (PT-15).
I've seen the RC version of this boat, very cheap, it's the same size and for only $16 you get everything including battery & charger and radio controller. But the details are not as good as the model version. The aft gun is supposed to be faced at rear. I guess "Tuk" the builder wanted to do something different. My former PT-815 which was built by another modeler named "Niphon" has it aft gun in 'normal' position: