No, putting a proper cord on it would not devalue the press. Whether the investment in putting the cord on would pay off - hard to tell, although I would not permit anyone to operate that drill press with that cord; and most people want to hear a machine running before they buy it.
The 150 presses are respected machines. You might wander over to Old Woodworking Machines (
www.owwm.org), register, and spend some time on the buy/sell board there, titled "BOYD" for "Bring Out Your Dead," looking at comparable drill presses to get an idea. Do
not ask on the main boards for its value; appraisals are against the rules.
If you plan to advertise it online, you'll need better pictures.