You'll have to call to check availability.
Note that ejector rod head threads did change so you need to be specific about the model.
However, Colt used the same heads for other models like the Official Police, original Trooper, other Officer's Models, etc.
If you get a head from the same time frame it will be correct.
Jack First Gunshop - First in Gun Parts - Rapid City, South Dakota
Poppert's Gun Parts Main Menu
Official Police listed, fits the OMS.
Antique Firearms & Colt Parts for Old Guns