Kevko oil pickup tube tab, run it or cut it?

I don't think you are going to get away with not removing that main bolt (but I don't see the issue there any way). There is just nothing else nearby. I'd be sure to take the torque off of both sides in steps and then re-torque both sides.

As for not using it, it might work out fine, or it might not; you are pretty much on your own there and that is the real message from Kevco. Who knows what vibrations might set up on that long tube and worry the weld or tube apart....

Whatever stud and nut you get, get grade 8 or higher and non-plated threads. And you may want to add a hardened washer between the nut and tab so the nut does not twist the tab when torquing down. (Plating effects the clamping force that results from a given torque.) The Kevco item might be a better part.... but I have not checked it out.