Problem with my trainwreck

Help guys! Ive got 3 lovely ladies from greenhouse seeds trainwreck growing in my persy. I veged them for a just under a month before putting them into 12/12. They have been flowering now for 3 weeks and still not a single pistil to be seen! Is there something wrong with them? There are loads of potential flowering sites coming up just no damn pistils to be seen anywhere!
Ive grown loads of other strains previously and never had this problem before.

are they getting light leakin' in?

I just got threw growing a trainwreck, the pistils took forever to come in, also growing a wild thai that has the same bud type and it took a while to come in. The buds are different growing than other weed, they remind me of ants boiling out of ground and make a mound. Hang in there they will come..rw

Thanks for the post roofwayne. I thought maybe I was doing something wrong. Guess I will just wait and see how it goes.