My laptop had a strip over these center batteries. I had to remove that before getting the center batteries off.
This heating with the iOpener took me forever. I tried my fair share of heating followed by nudging slowly with a credit card 1 mm at a time. Finally pried it off after 30 mins.
My replacement A1582 battery actually had holes for the screws, though my original A1582 battery only had the 'domed' rubber grommets. Anyways, putting in the OEM A1582 battery without anything in the holes worked ok.