I think his project was creating a diy camera based gun (like a diy Wii remote or Aimtrak). It would only use the shell from a Guncon 1.Jaybee on the arcade controls forum is working on a similar project to get guncon 1 working with any pc and any resolution. Might be of interest.
The guncon 1 and 2 are real light guns. The tech only works on a CRT monitor. The limitation re using one on a higher res CRT monitor is the chip which isn't fast enough in a Guncon 1 for anything higher than 15khz.
The only real light gun I/O boards I know of that work in 480p and above are the USB2Gun (from America's Army) which works up to SVGA, the Act Labs guns which work up to 1600p and potentially the USB gun I/O from the Friction conversion kit.