Help - Extracting models from .dat files of Mario Sports Superstars

[TravixMan]

I recently extracted the files of Mario Sports Superstars , though they seem to be heavily compressed as the game's files are contained in DAT files.

Here is a screenshot of the filesystem folder.


I am certain that the dat file in the ca folder contains the models for the game, as the first three bytes show BCH in the file.  



However, when I rename the extension from .dat to .bch and open it in Ohana, nothing shows.  Is it actually supposed to be for something else, or how would I be able to open it?