Those are no seed-like things, those are seeds. If you have autoflowers, especially outdoors, this can happen pretty fast. If someone has a Herma in a pretty great radius around you, you’ll get seeds for sure.
Automatics also often develop seeds in a very late stage… you do not necessarily see the male flowers, as they can extremely hide themselves.
Just take it how it is, and harvest. Your plant is ready as it looks.