The YCM color scheme is actually very accuate to the original prints. Lucas wanted the colors to look exactly as they had in 1977, but all the prints had faded--except the Technicolor prints. Technicolor is dye-transfer, not photo-chemical. Since Technicolor prints are hard to find in good condition (I believe they were only made in 1977), Lucas leant them his own personal 1977 Technicolor dye-transfer print, which looked the same as it had when he put it in storage twenty years earlier, saying he wanted the film to look like that. Consequently, the YCM timers used this as their reference. So the 1997 SE, barring deliberate changes in some instances (notably the R2-D2 canyon scene), is the best guide to the color scheme of the original film.
Unfortunately for us, however, it is largely lost--when the 1997 SE was put on home video it got a weird pink tint in the telecine. So if you saw it in theatres you had a faithful reproduction of the original prints, but everyone that saw it on video, in 1997 and 2000--meaning every release that wasn't the theatrical 1997 release--has seen something more useless than any other release as far as color reference goes. When Lucas put the films out on DVD, well, you know what happened with the colors there, and its unlikely that the 1997SE will ever be officially released ever again, and prints from it have all been recalled from circulation (and supposedly destroyed--this, unfortunately, may not be exaggeration, although they probably held on to some of the masters), so all that color restoration is effectively lost for all time.
The only rescue mission I can think of is if someone can get a print from the black market, which is not completely out of the question, but highly unlikely; if LFL in the future maybe puts it out as a bonus feature like the GOUT I would believe that, maybe, but if this is the case they are likely to either just use branching technology (i.e. 95% of the film will be the 2004SE color scheme) or have the individual alternate scene to view as a novelty, or simply port the video master used for the 1997 Laserdisk like they did with the GOUT, which would still have all the pink tint color issues, in either case not really doing much for us.