leptobolus seeds are elongated, the flowers, roots, seeds, and seed pods are different. the link i gave you was page 2 of a multiple page document about differentiating between the 2 any more info i'd give you would be straight from that or more googling.
but after reading (i'm going to harvest some soon too), the main thing i'm going to be looking for is the elongated seeds. that is if the seed pods haven't already fallen off
"Trust in your own wetware; your psyche and your body will be reunited." -Gracie and Zarkov
in plants we trust