You can mount them as is but the back of the rocker flexes like crazy and will lead to problems. Nick ties them in at several places which really makes a huge improvement.
https://northeastclassicfordparts.com/home/1048-mounting-bracket-set-for-amp-research-power-steps-1966-1967-1968-1969-1970-1971-1972-1973-1974-1975-1976-1977-early-ford-bronco.html?search_query=amp&results=15
https://northeastclassicfordparts.com/home/1048-mounting-bracket-set-for-amp-research-power-steps-1966-1967-1968-1969-1970-1971-1972-1973-1974-1975-1976-1977-early-ford-bronco.html?search_query=amp&results=15