Yes, they will be anamorphic: regarding all releases the following statement was officially issued.
"This region 1 DVD is remastered in a new 16x9 digital transfer, in a format preserving the scope aspect ratio of the original theatrical exhibition, enhanced for widescreen TVs. The DVD also includes an Elvis Presley trailer gallery."
I am very disappointed that Warner hasn't done anything in putting out a new remastered version of Viva Las Vegas on DVD with extras and a stereo soundtrack. Considering the great popularity of this Elvis movie, extra care should be given!