Installation:

You can replace either the knife or dagger with either the 6Kh4 or 6Kh5.

Installation path for knife:

mods\update\x64\dlcpacks\patchday3ng\dlc.rpf\x64\models\cdimages\weapons.rpf\

Installation path for dagger:

mods\update\x64\dlcpacks\patchday8ng\dlc.rpf\x64\models\cdimages\weapons.rpf\