But note that treatment and age can cause the pine to become harder. So even if it doesn't dent easily with a fingernail, I would still think it's pine.
Yeah, I can pretty easily scratch it with my fingernail, which seems the same as a 2x4 scrap and much softer than some oak and maple scraps I have around.
Also looking more closely at the bigger scratches and screw holes I see lighter wood visible, I was a bit fooled by the stain on the bottom.