Well I would have thought we'd see in Proceedings of the National Academy of Sciences... but as I say, it's not published yet.
Also people seem to be getting some facts mixed up. From the report in New Scientist, this gene-target has only been shown to block reinstatement of use, not the fact that the drug in habit forming in the first place.
Also, if this AGS3 is what I think it is (activator of G-protein signalling 3) it will cause serious side effects if given systemically (as opposed to directly into the brain).
Finally, I don't think the DEA will be unhappy about it. The DEA didn't mind about naloxone, and they don't mind about potential anti-bodie therapies, so they wouldn't mind about this.