There are a couple different types of hermaphroditic plants. I had what is know as an "intersexed" plant (see pic--see the "Nanners"?). But a true hermie will produce male parts much earlier in flower than intersexed. But if you see male ball sacks opening up early on in flower, you probably have a "normal" hermie. Mine was so far along when the males parts started that I decided to keep it. Trust me, it smoked real well.
Early on you look for both pistols and ball sacks opening on the same node. GL and grow on brother in hemptitude.
"mmmmmmm....Ganja"