The original brackets should be strong enough, they are 0.25 inch thick formed steel... smooth curves doesnt seem to have any locations where stress can really build up, i would suggest changing the bolts to new ones at least... the original ones would be old and might be more prove to shearing out if some very heavy loads are added. The bumper does weigh about 75#s all together, I can send you some drawings with dims on it for each part if you would like... well i can try i have solid works 2008 and i wonder if it will save as a PDF.
