Here is my take on truck beds. THEY ARE TRUCK BEDS. What you have is called character. It isn't all dinged up by a thousand blows from loose cargo. Unless you plan on taking it to SEMA, I wouldn't do a thing to it, nor even consider replacing it. I do not believe that you can take the bow out of the top rail without making things worse.
One other thing. Having that bow in the tailgate will draw prying eyes away from any other flaws which may be on your truck.
