Yup.
CTMA Building is in Mongkok. The basement of CTMA, where all the action is and where I got my MISB Grand Max, only opens at 4pm. So lots of time to do other shopping before that.
Sun Woh is just diagonally behind CTMA (not sure there are toy shops there anymore, but Sam seems to know of some).
There is a Gundam modeller's showroom diagonally opposite CTMA.