Just looked this up on Youtube, live version: Steve Hackett - In Memoriam Live (youtube.com) - And it is the same guitar used on Wonderpatch. I assume it's the GR500, no visible writing on it, but it seems to use a parallel port connector rather than a quarter inch jack plug, and the GR500 doesn't use a jack plug.
It's about time they do an improved version of the Somewhere In South America DVD ... Not sure if the recordings they have can provide a HD version, but the DVD has been out of print for 10 years or so ....