This seems to be a very nice stripe that you could probably call a "bold stripe" since the black lines going down the back seem nice and dark. The tail also looks as if it were originally striped as far as I can tell. "Dorsal" means "back" so all striped geckos will have their stripe there. However, on all geckos, even the banded ones, you will see a very narrow line running down the middle of the back. Sometimes the pattern even gets divided there and you'll see identical patterns on either side of this line (this line is exactly where the spine runs). In some banded geckos the line is a bit more prominent than in others and then some people call it a "dorsal stripe" though it really has nothing to do with the stripe gene.
it looks like either a dorsal or a reverse stripe to me, not a bold stripe... if you test breed to a reverse stripe you'd probably be able to tell, it's much easier to tell apart the different stripes in babies