Yeah, fawn is a blondish colour, basically you can look at the hairs under the dark hairs to see what colour she'll predominantly be. You can especially see it in that first pic, I'm guessing her face especially will lighten up to be mostly this colour
which I took from that first pic, but hey, I could be wrong, I'm just saying this from what I've seen with Ruby and lots of other pups here and other places, I found it hard to believe at first too! lol. I'd imagine she'll have a little sprinkling of darker hair on the top of her back but I wouldnt exactly call it sabling. Here's a pic of Ruby at 12 weeks and you can see she had a lot of dark on her face like your girl but it's all but gone now (as you can see in the sig)
I'm no expert, lol, but I thought I'd have a shot at explaing coz you said you were confused. But Gidget could easily prove me wrong, lol, she's such a cutie though!