From HR 218:
Sec 926B, c (5) is not under the influence of alcohol or another intoxicating or hallucinatory drug or substance;
Note the law dosnt say Possession, and according to the Court Case Involving the Off Duty Cop from Sturgis, (who had been drinking but was not intoxicated), in Sturgis Last year, the cop was protected by HR 218.
Since I dont drink much I'll not test the law, but I'm not checking my gun with the bartender when I take my wife to dinner at a resturant that does serve alochol. I just dont drink at all when I'm carrying.