Should be a nice new lease of life for those Vietnam 763s, they are mostly 1996-build models, with the exception of two 1992 build and a single 2000 build (ex-Citybird).
I would have thought FCA are getting the 1996 aircraft as they have the CF6-80C2B7F powerplants just like existing aircraft G-OOAL/M/N, the other Vietnam 763s are PW powered.
The existing aircraft are not due to get the enhanced interior yet.
See
Boeing Press Release about the First Choice new interiors.