I got this Colt AR  labled  Sporter Match HBAR.  Serial# 063xxx.  Has a bayo lug and FH.  How can I tell if this is a "Green Label" gun or not?  I'm new to these rifles and not to familiar with the specifics.  Also the barrel stampings read as follows:

C  MP 5.56 NATO 1/7

I know C = Colt and 5.56 is caliiber and 1/7 is rifling twist.  Whats MP and does this barrel have a chrome lined bore?

TIA

Yes, the barrel is chrome lined.  

Does your SN begin with MH? If so you have a "blue label" model R6601. Unusual for it to have a bayo lug from the factory but possible.

I have a some 6601s in the MH053xxx and MH047xxx range. They are both "blue label" Sporter Match HBARs with sear blocks, large H/T pins, small front pivot w/ drilled fence, and none came with bayo lugs. Your barrel may have been changed or the upper swapped out. You can call Colt w/serial number to verify your preban status.

Colt 800-962-COLT
CC001616 and Below - Pre-Ban
CH019500 and Below - Pre-Ban
GC018500 and Below - Pre-Ban
LH011326 and Below - Pre-Ban
MH086020 and Below - Pre-Ban
NL004800 and Below - Pre-Ban
SL027246 and Below - Pre-Ban
SP360200 and Below - Pre-Ban
1963 SP00001-SP00023**
1964 SP00101
1965 SP02501
1966 SP05600
1967 SP08250
1968 SP10750
1969 SP14000-SP14653
1970 SP15001-SP15473
1971 SP16001
1972 SP19401
1973 SP24201
1974 SP32601
1975 SP43801
1976 SP55301
1977 SP67651
1978 SP83400
ST038100 and Below - Pre-Ban
TA10100 and Below - Pre-Ban
BD000134 and Below - Pre-Ban (AR-15A3 Tactical Carbine - very rare model)
MT00001 and Above - Post-Ban
BK000001and Above - Post Ban (CAR-A3)
CST000001 and Above - Post-Ban (Began Late 1997 Production)
CMH000001 and Above - Post Ban
CCH010000 and Above - Post Ban MT6700, MT6700C and MT6700CH series, 1998 produ

The serial# does begin with MH.  According to the serial # list on the old site this is a preban rifle.  Doing some research I have found that Colt didn't ship this rifle with both the lug and FH.  They shiped with the FH only from what I can see.  Anyway I like the rifle very much!  I guess the barrel was changed or the whole upper was changed.  Is this a bad thing?  I hope not!  Also this thing about pins and what not.  The reciever has 1 pin just above the grip and another right above and in front of the mag well, both the same diameter except the one near the mag well has a "head" on the right side with a flatened portion that rests against a raised fence around the mag well.  Also this pin has small holes in the ends that would seem to be for a pin punch or something.  On some Colts I have seen a screw in this position.  Whats the difference, which is more desirable?  I got this rifle on a whim, the deal just fell together, did I get a good rifle?  I have a Bushmaster on order that will be here this week that would have been my first AR but like I said I just came across this so I'm naive about alot of the details.

Thanx for all the info keep it coming!  This site is great!

Correct me if I'm wrong, but doesn't "MP" refer to "magnetic particle"?  As in:  "Magnetic Partical Testing"?  Magnetic Particle Testing is a method of testing metal objests for small cracks.