This is a very personal question you have to answer for yourself. Many people want to turn every bolt & fix every hole. Others prefer to take the easy way out & buy new.
If you have the time, skill & desire to repair the original steel - go for it. Myself - I lack the skill to do a good job & I prefer to find a bolt on replacement.
I just replaced my passenger door because it had rust. I'll be paying someone to replace my cab corners.
