Christep is absolutely right about the "not valid before" date on the last segment being the key. If the INVOL reroute is handled correctly, this date is not updated, so you are fine. You can easily verify this at any time by asking any agent to read the date value on the last segment. If it happens to be in error, the AA RTW desk can correct it. Annotations in your record probably would not help in the slightest, unless your last flight is on AA (presumably it is not). I believe the policing on this is strict and automatic (computers are good at that); not sure what level of supervisor over-ride is needed if the date is wrong (but it will be very high -- so the airport check-in people will never be able to help you in this situation).