Fuel door tension?

[stavendirtbike]

I am currently in the process of buying a clean 87 chevy. I am already thinking about the little things I will address when I purchase it this week. It has dual tanks. Both fuel doors swing open, there is no tension to keep them shut. Is there a replaceable spring or something? I notice this on many 73-87 chevy trucks. All the chevy plow trucks at my job have this same fuel door symptom.

[jseifert]

  Truck has any replacement part that you would need...