I didn’t even realize, but the mandate to go IPv6 has passed for the U.S. Government. Not that it really mattered anyway. Until consumer devices ship IPv6 ready and enabled, and ISP’s start rolling out IPv6, this is just an exercise is what will hopefully save work later on.
Seems most Government websites I’ve checked so far that are IPv6 are using CDN’s to provide IPv6 connectivity. I’m betting behind the scenes it’s all IPv4 still.