Dude, the default hat is a BIcorne. It has 2 points, not 3. And the tricorne that hat pack you linked is backwards and has a skull on it.
Get the DTS blender plugin. Make it a tricone or whatever.
Then, just put the model and textures in a hatmod folder.
Its that easy. No scripting. No knowledge required.
I can make it for free, but I cant assure you good modeling. And youll have to wait for the weekends.