another dumb newbie question

alright kids,are we all ready for another dumb newbie question?here it 
goes..how do i know if i have a square as opposed round rear wheel well?i 
need to buy some patch panels for the rear fenders on the 77 midget,and the 
catalogs refer to square arch being available while the round aren't..well i 
dont know what the h*** mine are.any ideas?thanks..
  a very embarrassed phantom troublemaker
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