Maya, its been my experience that once a plant starts producing berries they are most likely viable even the first year, I know that some of the early years some wild simulated plants will have what I have called false flower heads, the plants look like they are going to bear seed but they ultimately dont produce any seed.
5prong, I have about 500 seed from last year that I have been stratifying on my counter top in a bowl, no sand or anything,just in a bowl sitting on a counter, I just keep them moist by watering weekly,well last month an interesting thing happened, I was away from home for about a week and when I returned I discovered that a mouse had found my seed,about 25 seed were cracked and eaten but there were less than fifty left in the bowl. I assumed that the other 400 seed were eaten as well but I was not able to locate the rest of the seed casings, 2 days later I was going out to the woods and I started to put on my pair of army boots, as I was putting the second one on I felt something inside the boot that felt like a pile of dirt, I pulled my foot out and dump the boot and found about 400 ginseng seed, so maybe mice will plant
a lot more ginseng seed than they eat.