Flip bumper on 55 - 59 chevy truck?

Someone told me that you can flip a front bumper on a tri-5 chevy truck by simply turning it over and bolting on, tried that and no way.. now I can make brackets but before I do I want to check one thing. The 58 59 bumper brackets have a different part number but run the same bumper, are these flipable or is making new brackets the only way.

Thanks

 

When I bought my 55 the bumper was flipped upside down. I'd say they just stuck it back on with a few bolts and didn't realize it. The brackets were never removed at the bumper, just at the frame.