It DOES look like an archback, can't see a brace, and it does have a very common color scheme for D25's with Natural top (D25NT).
I can only think of 3 other archback dreads off the top of my head, D4 (coloration's not quite right, think they generally had lighter sides), D26 (special limited run of D25, also had lighter sides), and G37/D30 (maple, again, don't think finish color's right)
Oh yeah there were also 3 a/e cutaway dreads that had arched backs, your choice of 'hog, maple or rosewood.
But this obviously ain't one o' those.