Yes, they could be female, although they could be a hermaphrodite. I have had good luck growing seeds I have found in bought weed before as long as there were only a few. You have to gamble though and I would only do this if the weed the seeds came from was phenomenal and you have the time and space to experiment. Also keep a vigilant eye out for hermis as they are sometimes likely to show up. That said, you could get some killer cuts out of the experiment, but I would never breed with them. Hope this answers your question and good luck!
TGT
i actually ran a bag seed from a friend.. he got a sick bag of og kush .. and a couple other strains from a fellow grower.. the grower said he had a light leak and stressed all his 3 strains to hermi in week 6 or 11.. there were 43 seeds found out of 22 plants.. just a seed here and there.. he found a keeper clone only out of the seeds and shit is fire.