I was in WalMart and they had a Colt LE6920SOCOM. It was 400 higher than the LE6920. I could see that it had an ambidextrous safety. Both had A2 front sight and flip up rear sight. The SOCOM has a quad rail where the 6920 has the stock forepiece. The books are different also. The 6920 is Colt AR15 Carbines and Rifles while the 6920SOCOM says Colt Match Target Rifles. Besides the cosmetic changes that I have noted, are there any other differences such as better trigger or higher grade barrel, etc? I did not see $400 worth of differences on the outside.