It depends on how badly it'* rusted. Mine on the left side is rusted out beyond belief. I recently sanded it and sprayed some rubber undercoating over it for now. But back when I first exposed the rust, I unscrewed all 4 screws, to find that 2 of those screws were completely rotted out. There is metal in the seal itself and I need to replace the seals since it'* all rusted inside. That seal is held on with 2 screws now
I recently took off the right side seal and found it was rusted underneath as well, but not as badly. However the metal inside the seal was completely rusted out so the screws were not able to hold the seal back on. And last Friday I lost the seal as it fell off as my friend got in the back seat. I noticed it was gone the next day..