The GW cruisers were never realized, however if they were, they probably would have remained in service all the way to the 80s due to the lack of fundings to build new ships of their size. In this case, modernization is very probable.
Possible modernizations include:
1. Installation of Harpoon missiles mid-ship and aft.
2. Installation of new radars
3. removal of Turret B and sea cat missile launchers
4. Installation of two sea-dart missile launchers