I have replaced a dozen or so over the years and other than never having enough hands to hold the gasket, trim piece, screw and screw gun at the same time, it's never been a problem.
Now I have a couple or three Whirlpool/Roper refrigerators in rentals and when you peek under the door gasket, there is no hardware. The lip of the gasket is behind the inner door liner and it appears that the whole mess is glued to the door.
Are these things replaceable or do they expect you to just buy a new refrigerator when they fail?
John