Its a rare headphone, and a collector's item. Maybe not worth the price to some, but well worth it to collectors. The lettering is not perfect, but it in much better condition than most i have seen. So, I would say that this is a real nice collectors item, and probably a great sounding headphone to boot. It will only appreciate in value over time.
Another interesting point is that the listing mentions Joe Grados offer to personally service the headphones. I wonder what that is about, and how common that is? Very interesting. It also appears to state that Joe does a modification to the headphones to bring it up to current spec (whatever that means), and that Joe allegedly says the results of the modification is "incredible." That is interesting stuff.