Colt says that since they re-introduced the AR-15 with all the "evil" features like collapsing stocks and threaded barrels, they decided that since there was really no difference between the Law Enforcement AR-15 and a civilian AR-15 of the same configuration, they would just sell the same rifles to both markets.
According to Colt Firearms, Colt Industries, maker of military and Police M16 and AR-15 rifles just "pass the rifles over the wall" to Colt Firearms seller of commercial guns.
In other words, all the M16 and AR-15 rifles made by Colt Defense are made to US Government standards, and a commercial buyer is getting the same semi-auto rifle a local police department gets, and it's made to US government specs.
Further, no matter where you buy a Colt rifle, it's the same rifle.
If you buy it as a police department, as an individual police officer on a department purchase, at a local gun shop, or at a Walmart store, you get the same mil-spec AR-15.