Employers are allowed to identify an employee as disabled if they know for a fact that it is the case. Your company will have to make a decision if they want to use only what is being provided in the self-identification forms or override the form based on their knowledge. I think that most employers are selecting to use only the information provided in the self-identification forms. Keep in mind that the OFCCP cannot penalize you for not having enough IWDs or Veterans because of the voluntary nature of the self-identification process. I have been told that the terms that define someone as being a disabled veteran may not necessarily make someone disabled under the Rehabilitation Act or ADA; however, I am not totally sure of this. I would say that if you rely on the responses to the self-identification form, you will be safe. I have not seen any further guidance with respect to differing responses on pre-and-post offer self-identification forms; however, there is nothing stopping you from following up with the employee to confirm their post offer selection. Your idea for providing OFCCP with two different counts, one based on the responses to the self-identification forms and one based on your knowledge, would be okay to submit during an audit. I'm not sure if the different counts will really make that much of a difference in the long run.
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.