I think they will go down very well.
Whilst for me their last truly great album was ...and Justice For All
, released in 1988, they are still a great live band.
Set-wise I would have thought it will be "commercial" Metallica, so most of the Black album plus the more commercial tracks from their other albums, they have already said they are thinking of opening with Oasis' Wonderwall
however I doubt they will do their cover of The Anti-Nowhere League's So What?