Does Dipper ever explain/show Bentley the birthmark on his forehead?? Or do both he and Torako assume “Dipper” was his name from the beginning?

Mod K here! I’m sure that the birthmark comes up at some point, especially in their college days when they’re literally living together. At this point, Dipper really is Alcor’s name–it’s the name that matters, at least, and Bentley (and Torako!) are satisfied.

I mean, things have changed in two millennia, Dipper could have totally been a legitimate name in the early 2000s!