Male pollen sac on my autoflower?

Yes, that is a male flower forming. From this size it will be about another 10-14 days at a minimum before it is mature enough to release pollen. After looking at your diary, your plant looks plenty mature enough to me, that I would be harvesting it anyway. Even if it does release pollen, it will take another 4-5 weeks for the seeds to grow to maturity. Some Cannabis (female) plants produce these male flowers right at the end of their lives, just before dying, in a last ditch effort to produce seeds for the next generation. This is also why when close to death, that they will sometimes also have a late/last small flush of new calyxes with fresh white pistils, in an effort to try and get "pregnant" or fertilized. Usually the pollen from these late male flowers is ok to use, however, you can also have a situation whereby you inadvertently breed plants that have a preference for producing male flowers, so in my opinion, it is not ideal to use the pollen from these late male flowers to breed from. Far safer and easier to buy seeds from the professionals or if you are interested in breeding, using pollen from pure male plants. This will provide seeds with far more stable genetics. As your plant is both producing these male flowers and late fresh calyxes, this tells me she "knows" time is running out in her life, and to leave the plant to grow any longer will just result in a lower grade of THC, as by the time this is all happening, the plants' metabolism has all but ceased and more THC is breaking down into CBD and CBN, than any new THC is being made. If you would like to see some pictures of what will happen with those male flowers once they grow, go to my diary called "Sweet, Sweet Seeds" #3 and look at pictures 29, 30 and 31. The male flowers in those pictures are about 6-8 days old and still need another 8-12 days before they would release pollen, had I not cut them off. I ended up throwing the whole plant away as those male flowers, were sprouting everywhere! Interestingly, that plant was from a "twin seedling, which can be seen in picture 27 and 28 in the same diary. Hope this helps,.... Organoman.