I don't see them performing standard shows as Beastie Boys. Mike has played beasties' songs and rapped his verses over them, but as an extra of a DJ set, not a proper band show.
I can see them doing small tours and appearances with the ocasion of new releases, but more like theatre or ted talks -ish than actual music performances.
and I see very possible, in some years, the release of new (old) material, probably in a genuine and creative way, as the beasties always do.
i.e. for the hundreds of hours of recordings of the G-Son studio, they could open those files for nice producers and/or bands to take samples, chop them, mix them and finally get new music powered by the beastie boys