Rear Bumper Brackets Install

[lkt1954]

Getting ready to install the bumper on my 70 C10 that now has frame mounted fuel tank installed.
That leads to making it difficult to tighten the rear bumper brackets without dropping the tank.
I'm thinking about welding the nuts to the brackets, mount brackets to the bumper, then installing the bumper.

Is there any reason not to do it this way?

Thanks