There's a shitload in khaki... Most since 2009 are. Just search for "MARSOC", "MSOB", "MSOT" and "MSOC" on dvidshub and you'll be happy
Your options are correct, however MAR-CIRAS in MJK would still work. The most common, currently, is probably the PC with cum. RBAVs aren't *that* expensive... look on SKDtac and such. But yeah they're more expensive than other options, like the EIPC with cum for about 175$. For the real one (commercial version).
If you have a block2 gun with the Daniel Defense rail, do you have the 9in or the 12.5in one? So far, MARSOC only uses the 12.5in one.