Only you can tell if that's something you can do. However, theoretically, if you have taken Nal to control your cravings during abstinence, you haven't "achieved" anything in terms of being "cured" of alcohol as Dr. Sinclair would describe it. In other words, the circuitry in your brain is still wired as it was when you were a "raging" alcoholic six months ago. When someone is "cured" per the Sinclair Method, their brain is wired as though it were pre-"raging" alcoholic. What is different now is that you have exercised self-control, gained some rational power over alcohol, and certainly developed new habits. However, Sinclair warns about the Alcohol Deprivation Effect whereby, if you were to start drinking today (with or without Nal), it's likely your consumption would be even higher than it was when you stopped drinking, at least temporarily -- picture a sailor coming onshore after a long tour and having beautiful women grabbing all over him.
On the other hand, surely millions of people have given up drinking for a bit and then subsequently practiced moderate consumption without taking a pill. So, you're obviously faced witih the decision to keep your happy life as is

, or try to make it even happier

by introducing an occassional drink into your life, meanwhile risking a return to whatever probablems that made you quit in the first place.

It's a lonely place to be, but only you can make that decision. A lot of people would suggest doing an "experiment," i.e. taking Naltrexone one hour before drinking in a very controlled environment to see what happens (e.g. with a supportive buddy or loved one present to keep you from going on a bender). If your "on" Naltrexone via an implant or injection, then you might just wait a bit and then switch to tablets, as the Sinclair Method itself does not use all-day Naltrexone but uses it only when paired with alcohol consumption.