Example:
On your first on call day following your last non-fly day, you check your schedule at 0200 base time. After that check, you are then required to acknowledge a trip assignment no less than 3 hours before sign-in (the earliest rotation/SC assignment is 0500 on your first on-call day). Scheduling has assigned you a rotation that reports at 0600. Are you legal?

NO. According to FAR 117, you are not legal because you need at least 10 hours rest before starting a flight duty period. In this scenario, the earliest report for a rotation is 1200 (i.e., you acknowledge assignment at 0200, add 10 hours of rest, which brings you to 1200).