If you select "Premium" or if your device is under Samsung Care+, the confirmation email will explicitly mention enhanced service. The return address will likely be . Keep that email as proof.
If the barcode on your shipping label is damaged, the Dublin center may open the package but not know which IMEI it belongs to. Write your IMEI and RMA number on a piece of paper inside the box. Do not rely solely on the external label. samsung po box 12987 dublin ie imei extra quality