Yes they are all like that, the spring is flat so it can seat in the clutch assembly perfectly!
Don't worry they are all supposed to be like that, I take it you haven't taken the OEM one out yet have you? When you do you will notice the OEM one will also stand up on its own with a flat top and bottom (a lot of springs are like these) the difference will be that the OEM one has much thicker metal for the coils in the spring. The OEM on has a very strong spring rate I think it was like 300lbs or something like that if my memory is correct..... my spring that I offer I believe is rated at 70 or 75lbs.