Two things:
- You received an interview appointment letter only (not oath). Assuming you pass the interview and are recommended for approval, you may be able to take same-day oath (if available at your DO) or more likely will be sent a separate letter with oath appointment.
- Name Check is something USCIS requests from FBI in parallel with finger prints. All recently scheduled interviews (June '06 onward) should already be namecheck complete, so you probably don't have to worry about it too much.