not trolling, just genuinely interested i mean if you can take a clone from a 3+week flowering plant (flowering clone) then what is stopping you taking one from an Auto?
You might get roots, but what would be the point? It will finish out its life cycle, and you will have less yield because that part of the plant finished flowering with no root system. You will not get a new autoflower plant to grow a full cycle with. The clock starts when the seed cracks.