GR: Unless you can convince the USMC of the need to redesign and manufacture the appropriate section of the aircraft [to regain the original internal weapons spec] that will be an expensive, single nation, endeavour indeed.
AFAIK They have their original weapon spec of 1x 1k lb and 1x aim-120 now. It changed to a 2k lb and then went back to a 1k lb. The same as the UK did with the C and then back to the B.