Lockheed Martin already lost this battle. The "MAT-V Ultra Domination Edition"/JLTV is already in rotation with the USMC and it would be insane for the Army to not leverage that parts commonality, maintenance experience, and procurement lines the Corps already have (in terms of SL-3, SOPs, NSNs, Mods, etc). This is a "BIG" win for the DoD, and makes too much sense for Lockheed to have any case. Even if they have a case I am pretty sure the Government will just "Crye Precision" the situation and do what they want (hopefully with a win this time).
...I hope this is the time they pull the Deebo, but we shall see. Long live common sense!