The current quotes from Lockheed are that the C130 J will have systems from the latest P3 with the addition of open architecture to allow for system expansion or upgrades.
You can have full ASW/ASUW capability dependant on service requirements. Weapons bays are attached on the fuselarge as well as 4 wing hardpoints. The system is designed to be roll on roll off in a day.
The current bumf that Lockheed has released (even if it is the sales pitch) states that only minor testing is required for the system to be ready to progress to the installation phase. They also quote the UK as one of their primary targets for the equipment fit.
Could be the way ahead.