Magnetic Fridge Freezer Door Seal -130cm x 70cm for ZRD33ST Stock Number: ES1539567

this is a universal seal.....does that mean its a length of door seal "rubber" that I then, measure the top,bottom,and both sides of my freezer, and cut the length to my requirements, my door seal is 54cm x 77cm ....and if yes do I then have to mitre all the corners to create an all-round seal ?? watched the relevant video on fitting these, but mine would be different to fit, cos replacement is 130cm x 70cm....and i only need 77cm x 54cm...so I would definitely need to alter...Is that possible to do ??