RV fridges are condenser type and thus have no air movement at all inside.
So anything that can be done to help with air circulation is a good thing.
Yes it will help with cooling, and help with preventing ice build up on the cooling fins.
One can use just about any 12V fan, like a computer case fan, you need to find a 'hot' wire at the light to power it - to make sure it stays on with the door closed.
This one looks cool in blue, 2 little fans and it improves everything all around and it cost less tha 3 gallons of gas