Drilling or screwing screws anywhere could spell trouble. Once you hear that hissing noise its to late you have ruined your refrigerator.
They have hot gas loops that run around all sides and the front dont do it. Same goes for the inside unless you have a tubing diagram just dont do it. Even then the tubing can be off a little due to the foaming in place.
As long as it is frame tight to the top of the refer and a couple of anchors at the front bottom frame you should be good.
Good way to tell if the refer has good airflow is to open the door if the frame is really hot you dont have good air flow or condenser fan motor has failed.