In another thread, you asked about HUD Cat 3 operations. The HUD is a fail-passive system and as such does not use an alert height, only a decision height. Some operators use a dual autopilot autoland system which is fail-operative, and their alert height would be defined by their op specs. One does not mix HUD and dual autopilot procedures during a Cat 3.
Thus the answer to your question is really airline specific. If you are currently employed by a 737 operator, ask your training department. If you are looking to get hired by a 737 operator, they will let you know what procedures they use.