For watches with value less than RM 500 incl shipping, no GST is levied.
For watches above RM500 incl shipping, 6% GST will be charged. Depending on what shipping service you use, will determine whether you kena GST or not.
Registered airmail: Maybe/ Maybe not. If kena, Pos Malaysia will ask whether you want to appoint them as agent (approx RM 70) or pay yourself at kastam office.
EMS: Sure Kena. Pos Malaysia same as above.
Courier (DHL/ Fedex etc): They will call you first then clear customs for you and you pay them incl service charges. AFAIK quite expensive i heard.