There are modifiers in place but collapsing them in order should produce no issues. You can remove subdivision surface totally if you wish.
Everything is parented to the "Grip" for transformations.
You have control over the folding mechanism under the contents of "Hinge_Control". The mesh labeled "Knife_Hinge" controls the folding of the knife itself. For added realism you can potentially rig "Release_Hinge" to pivot the hinge to animate the release mechanism.
Do not apply rotation transformations under "apply rotation" (Shift+a) if you want to preserve the rotational controls.