I have never come across a strain that did not reveal its sex once it became sexually mature in veg. The time can vary though. But usually by week 5 or 6. The preflowers may be small and hard to see without a magnifying glass. But they will show. The third or forth node from the top is a good place to start looking.
I've got an Indica dominant strain (still unknown/bag seed)I've been growing for over 60 days under 16/8 light that isn't showing at all! Yes, it has growths between the nodes but are not sexual parts at all but possible new branch sites. Most have grown but then stunt out as it's using all its resources for rooting and light sourcing by vegging out. My light schedule allows enough dark to accumulate enough phytoestrogens to "know" its sex but focus on growth. This is the problem with 24 hour light growth schedules, there is not time allocated for sexual production and this then coheres with how the plant was brought into the world...clone, male to female pollination or hermaphrodite to female pollination..mendels law....
Alot of info here is absolutely false and it takes more than a weed grower to define these scientific properties of plants both mono and dioecious. Man o man i could go on but the point of this reply is, even though i have a plant with unknown origins i know I can vastly influence the ultimate sexual orientation of my plant despite being in a vegetative state merely by being patient and respond to it's individual needs in a timely manner. Just be patient, don't stress your plants by taking cuttings or forcing, etc....with experience comes knowledge, not others opinions.
