You’re fine, if asked about it, disclose. I think you can easily mitigate why you didn’t list the charge if it comes up (advice of counsel, etc.). Depending on the state the charge and subsequent expungement took place will dictate if an FBI/state police records check will reveal the charge. So, research your states expungement laws - you’ll find your answer there. Also, I recommend calling the state police bureau of identification where your charge took place and obtaining your record (RAP sheet). I’d also like to add - most expungement attorneys, at least the ones I’ve been exposed to, advise their clients to destroy all their personal records related to the incident (police report, expungement order, etc.).
Reference the following article: https://legalbeagle.com/5073501-long-police-records-kept.html
The FBI does comply with state expungement orders. Is the FBI obligated to do so? No, however they do so at the request of state police agencies all the time because the states are the custodians of said records…So, pay no attention to individuals who tell you otherwise.