The 197 has been operated by a 744, so I'm guessing that for the summer timetable it is going to a 777.

If you keep an eye on this link http://ftdashboard.net/dest/iah.htm you will be able to check out the aircraft flying your route and that will give you an idea of which aircraft you can expect.

Then you can use this link http://www.thebasource.com/boeing777-200.html to check if those aircraft have AVOD or not.

Sorry, to add, there's no way anyone will know what particular aircraft will be flying that date