Could do but try running a warm hairdryer around it first as it may just be a little deformed and heating it up often gets then to spring back into shape. Worth a go before splashing out on what will no doubt prove to be a costly replacement door seal.
this unit is a single cooling f/f and it the door is either closed fast or slammed shut then when the door closes it forces the air from the fridge side back into the freezer section and pushes the door open.
if the appliance is leaning slightly forward then this will then cause it to happen more often.
Does the door stay open if you open it about 3 foot ? or does it open more or close ?