I got a chance to check out my brother's 6.4 mil CMPInland a couple days ago, and noticed it has a 4 rivet shallow groove handguard. The hanguard has the "brass/copper" color to the rivet heads. The stock that came on it was beat up pretty bad so he changed it, but it still has the handguard from the CMP. I'm thinking it must be a USGI handguard, rather than "commerical." I'm curious if you'll find any of these in your search.
Thanks, - Bob