8" apart makes me think they might have been planted there actually. You might have found someone's patch.
But, I did try to find mention of ginseng in the New Jersey laws to no avail. The best I can tell they just do not consider it something that requires regulating within the state and certainly not for export. However, it is still a CITES II listed protected plant, so you should only consider harvesting if it is not protected in your state. In other words, you need to make phone calls and spend a lot more time searching than I did to find where ginseng either is protected or is not protected within the state of New Jersey. You might start with your local wildlife folks, and from there go to the agriculture people. This varies by state who controls the ginseng program. In your case, there isn't even a program so finding out where ginseng fits in might be a little more difficult.
Another think that doesn't make sense is that you are saying you found plants with berries in the spring? That's not right. The berries ripen in the fall and seldom last to the first hard freeze. The whole tops die back. So finding plants this early with berries make me think this might not be ginseng you are looking at. Did you take any pictures?