Apologies for the late reply, all of the assets are in FBX format and exported from Maya. Blender uses a different rotation axis so the bones will not import correctly.
If you wish to rig another hand model but use ours as a base, you will need to set the import options for the FBX to import using the same axis as Maya and Unity with Y Up, Z forward and X to the right in Blender.
I hope this helps