66 c-10 crooked crossmember behind differential

[Banjo]

Is there some reason my stock swb has a factory riveted crossmember just behind e differential? In middle of mustang gas tank install would be nice if it were straight, and I have no issue knocking out rivets, but, on the driver side it meets plate that holds the bar running from differential to frame bracket. I guess this is called a locating or pan hard bar, don't know. But given driver side riveted to that bracket, don't believe I can just bust loose pass side and push crossmember forward 1.5", or whatever, and bolt it back down? Thanks in advance for your thoughts