Blue cuckoo Marans at 15 weeks - pullet or roo?

[Hip Hillbilly Acres]

This is our 15 week old blue cuckoo Marans, Clementine. Got her from Meyer - obvs hobby quality, no feathered legs or anything. To my untrained eye she seems like a pullet, but I've gone back and forth since she was a week old. She's our only Marans and have nothing to compare her to. Her barring is quite dull, and I'm guessing a cockerel would show more contrast. She was slower to feather than all her brooder-mates, and her tail feathers still seem pretty stubby to me!
Thoughts?

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How cool: I have some birds that look just like the ones in the rear. Looking at my notes that bunch were among the 4 Welsummer pullets; assorted 3 Marans (straight run); and 5 Dixie Rainbow pullets. Now I now what the hey they are (the ones that look like these).