Technically, the regulations require posting of all open positions that are three days or more, not filled internally, and not at the management level in the organization. However, OFCCP doesn't seem to have a problem with not posting when there is a rehire of a former employee and no other candidates are considered. On a purely practical level, it makes no sense to post an opening when you know exactly who will be hired and you know that no other candidates will be considered. This doesn't mean OFCCP won't ask what happened in this situation during a compliance review. The agency is always concerned when it sees data where there is only one applicant for a hire. Unless you get a very problematic compliance officer, OFCCP is likely to accept the failure to post when there is a rehire.
You can use this OFCCP audit checklist to ensure you're doing what is required to maintain OFCCP's regulations including VEVRAA, Section 503, and EO 11246. Or request a demo to streamline your compliance and recruiting efforts.