i agree, if they can show proof(aka:a page with the SAME look) then you should change but really a page design cant be protected, at least i never heard of it
now if you copied a program and called it your own, THEN its copying. but if you think of it design is really just some colors and graphics and you can get graphics anywhere and have the same chance of getting the same thing as someone else.
but if they didnt show the paten code, then who really knows if it is safe. but for all u know the dude himself wrote that saying he was a lawyer. i say ask fore the code and then see if its real.