Like Althor said all I can do is grow it out to see if it's a herm. I would normally do this outside incase it is. I always grow herm seeds outdoors. Haven't grew a male in years because of it and who cares if it herms a little outdoors. Never had a full blow herm outdoors either.
I also learned a trick to tell the difference between morphs/males and females apart by looking at the seed. You want the mark where it was attached to the plant to be perfectly round. Hasn't failed yet