I don’t think the FAA pulls anyone’s medical records it is up to the applicant to be honest under risk of $25,000 fine I believe is what is listed on the application that you sign to acknowledge. If the FAA should find out you have a diagnosis of apnea that you failed to disclose that would not be a good thing.
Here is an FAA info sheet on OSA
https://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=18156