The IKEA TROFAST End-stop is designed to stop the containers in your TROFAST furniture from sliding out from the back, preventing wall damage from the containers being pushed against it. Using this end-stop does not require screws, so it will not damage the wooden furniture.
If you need to turn the TROFAST around, simply take the screws with the end-stops and switch them to the other side so the end-stops are on the correct side. You need to print one straight and one mirrored for each container.