Yep, definitely the color of the fur that's confusing people. They can come in a smut color, often referred to as a sable. Sable appears to be different from breed to breed, so don't let that confuse you. I have a dog who's 11 yrs old and when I adopted her at 6 wks we thought she was APBT
... turns out, she's got Chow and ACD (Australian Cattle Dog, or Blue Heeler) in her and that's what gives her the full prick ears. Just to show you her color, here's some pix of her... I never really settled on exactly what her color is, although everyone thinks she's either GSD
or Rottweiler due to her tan points. You can see how her color changed as she got older from two-tone brown to black and brown (or sable) with tan points.
Alyia as a 7 wk old pup
Alyia as an 8 wk old pup
Alyia at 12 wks old
Alyia at 2 yrs old
Alyia at almost 3 yrs old
Sadly, I don't have any current pix of her as my ex-husband is reluctant to share anything lol. She's now 11 yrs old (as of July) and is still as beautiful as she was then, with a few grey hairs in her muzzle.
I'm sure your pup will be gorgeous when it's grown.