Unity Model Formats

So I’m looking into porting the surgeon simulator content into SFM, but when using the Unity Content Explorer, all I get are these unknown file formats named .43

Anyone know how to get these? Someone made a maxscript for them but that doesn’t work apparently. Here’s that script: http://pastebin.com/i7JZFapg

Here’s a .43 file to test with (heavy’s head)