I made a false assumption that the vendor was making his or her own Lugol's. But with the vendor selling J Crow's, you should be okay. Are you worried about it being counterfeit? I'm more likely to believe that people sell what they claim, most of the time.
Lugol's 2% has 2.5 mg per drop -- 1 mg Iodine + 1.5 mg iodide. You've made a good choice.