hello, thanks for your interest! you should be able to use Blender to unpack the files stored inside of the .blend .
Open the blend file.
File > External > Unpack resources. This will spit out all of the texture and normal files for the model .
I don't remember if I used an Occlusion/Roughness/Metallic map for this model.. but I hope you know how to figure that out in Maya.