Don't claim to have actual knowledge of something and then act like you are to important to actually share that knowledge.
And, your knowledge comes from where?
All right, but it will piss you off. DEA, at the time being the largest owner of Colt rifles in law enforcement, asked Colt to provide some pretty normal service after the sale, (new magazines for the huge inventory of 9mm SMGs DEA was issuing at the time). Based on those negotiations, DEA decided that there were tired of dealing with Colt as an almost sole source supplier and decided to do see what other comparable brands were out there (DEA was already buying some H&K 53's, but wasn't happy with the H&K safety and trying to incorporate it into their training protocol).
Instead of going to experts such as yourself on the internet, they decided to try something novel-to take all of the major brands of AR's and similar .223 platforms, and test them to objectively see which ones suited DEA's law enforcement needs the most.
The result were three guns passing the tests, Rock River, Colt and Sigarms. Dissatisfaction with Colt's service after the sale already being the reason for doing all fo the testing, and the Sigs being a slightly different platform that would require lots of new training, the people making the decision at the FTU, unanimously picked the Rock River as the rifle they wanted to buy and put into service. Federal contracting rules being what they are, Colt and Sigarms, also got contracts (which as previously noted, are not contracts in the traditional sense as you might think, but rather options to buy at a particular price, something the federal government does with everything from bullets, to pencils to tires). It doesn't mean, as many people like you seem to think, that DEA was obligated to, or in fact did (as far as Colts and Sigarms), buy any guns under any of the contracts.
Now as far as off the shelf being the same rifles DEA gets, I admit I have no idea. I know I have one of both, and they sure seem to be the same quality, and sure shoot the same (and yeah, I have a Colt AR, too).
Now unlike your stuff, does this really sound like something I pulled out of my ass?