I don't think it's fishy, but I think the, essentially, black spray/tint over the repair area was a bad move by whomever did that. It makes it look like it's hiding something...The repair could be rock solid, but you can't even tell. Kind of a turn off.
Some slightly off-topic questions....How do you store something at home that's valued upwards of 20k? Most people don't have anything like that at home (outside of what's in their garage). Are you selling this because it's too valuable nowadays? Is it just kind of weird to have this sitting under the bed or in the closet or whatever? Do you actually play it or is it too valuable to where you don't want to put more wear on it? How did you have the appraisal made? Did you just mail the guitar to Gruhn? How does shipping insurance work on that?