I am getting the usual water collecting under crispers. Determined that the Through Drain has rusted. I have located part number AP2064813 as the replacement. My question is, do I also have to replace the Gasket Through, part number AP2063339? Also, correct me if I am wrong--to accomplish this replacement, I will unplug refrigerator, unplug and remove ice maker, remove back panel, remove freezer door, remove front trim piece at bottom/exterior freezer (facia) which then allows me to remove the bottom freezer panel accessing the Through Drain. It looks as though there are only two screws holding the Through Drain and I should not have to remove anything else--right? Thanks in advance.