Well, since the weapon already fires a 'missile' why need MCAR?
Anyway, as MCAR relies on gamelogics placed on correct positions on a vehicle weapon, which is not possible to do with a infantry weapon model, I have my doubts if any of the code could be used as is.
I'm not 100% sure on this but as far as I can remember basically all of the MCAR functions and such rely on the data from those game logics, apart from maybe some stuff directly related to some of the guidance 'maths'..
sa8gecko did make a MCAR based TOW guidance script set for ArmA (1) many many many years ago but that code is most likely in byte-unexistence since forever, could be that it didn't use any of the gamelogic stuff as it was no longer needed in ArmA due to it natively supporting missile weapons on car class vehicles..