On our third GSD now and they all had at least one spot.
Our newest girl has 4 of them, all toward the back.
My 2nd gsd had a spotted tongue, I was told it comes from European heritage, like if your mom has a birthmark on her cheek, you might also. Tho i cannot verify the European heritage, that is what I was told. And I have gotten all my gsd's from pounds or a rescue. So I can't ck out the parents... Let me know if u hear more