K, I'm not experienced at molt sexing, given. But those look like they might be male accessory organ... ? Because I'm not seeing a flap/uterus externus or the wider slit opening, those horns are wider at the base, and Brachys are pretty notorious for having deceptive male accessory organs. So... Thoughts?
@Feral You have to take the size of the T into consideration. This moult has only a leg span of 4 cm (not even 2") and at that size, you wouldn't have the male accessory organs this prominent. Also, the spermathecae aren't fused when they're still small.
This is my male T. albo one moult before he hooked out (moult is 3,5"):