For me, it doesn't matter. I probably need to get all this info OUT of my head. But even if you organize by color, when people post their bag of X color, they can state its year and season, like spring 2004 light yellow, and any name variants. That might be enough and shouldn't unduly clutter the reference pics. For that matter, could a Mod move posts into chronological/season order within a color section once the posts grow in number? Sorry, mods, lots of work, huh?
If grouping by color is the consensus, you could still (without reinventing the wheel) have a BRIEF, separate section that merely lists, by year/season, the colors produced and notes the hardware produced. It would be a one time LIST, only to be updated as new seasons come. Then you would have a sort of cross-reference within the forum, but pics only in one location. Just a compromise suggestion, for what it's worth. If you picked a blue, for example, from a year you feel has desirable leather, you could then go to the pics and compare your blue to all others.