Recommend you don’t reinstall the rack that most people delete due to the rust you speak of. Instead, look into getting those holes permanently fixed via welding or other method that has been documented in this forum.
If you’re hell bent on putting that rack back on then I’d suggest looking for a better way to inhibit the rust. The roof rack were port installed in the s***tiest way with rivnuts. Assuming the PO drilled those out and now your holes are wallered out. You may need to step up to a bigger size. Again, counter to what I would do.
Why do you want this rack anyway? In my opinion, it isn’t practical and the gain you get in a subpar roof rack, you lose exponentially in the corrosion of your otherwise good roof.