Honda speaks the truth.It's not just a gasket failure, Honda says the groove that it sits in on the upper section could also be to blame, that said you get a decent amount of part for $200. Shop around, look for part number 15810-R70-A04. I sell at least 1 or 2 a week and supply a copy of the bulletin to those who want one.
The problem lies in the matting surfaces.
200 is a lot cheaper than a new denso alternator if you non oem gasket fails and soaks your alternator in oil.
Or worse, during a cross country road trip.