Not sure about that, tamahagane is such a high quality steel, that if someone was to make a razor from it, they'd be sure to stamp it as a mark of its quality.
The steel has that sort of crude, unpolished look that's typical of tamahagane, but I think that could just be a feature of all japanese steel.
Here are the markings for tamahagane
http://straightrazorpalace.com/attac...agane-mark.gif
What does the omote side look like? That's a better indicator of the wear. If the omote is covered in scratches, that's the hone wear. It's more important to look for hone wear on a kamisori than a western because they were made with soft steel on the inside and hard steel on the outside, whereas western razors were made entirely of hard steel. Because of this, they need less hone wear to no longer be salvageable.