the real question here is about the condition of the movement (and seller indicates that he cannot open the case . . . which raises the question, does he lack the tool or is it rusted shut?
if the dial and hands are this rough, then what should we expect of the movement -- a rusted lump or serviceable? generally, it seems that the condition of the movement will be similar to the condition of the dial, at least when they have lived together.
while I am usually happy with some age or patina, or even signs of hard living, on this one I would ask myself what you are actually buying. if not dial, if not movement, if not case (and pushers), then what?
still, if it will even give forth a "tick" of life, then I would guess that it's worth $600 to $800. every once in a while, we do see the dials offered for sale.
Jeff