I haven't found a great way, but there is a "Classic Era" category and a pre planar gear page. However be warned, I have noticed some incorrect info in the Gear section (i.e. Wu's armor for monks). Also, the patch notes are a good way of seeing when certain items / quests were added.
The great part of the wiki is that anyone can update it and you could start aggregating classic info into it's own page, or come up with a cool category of your own. I'd do it but I never played original and don't have a great set of knowledge on the subject.
http://wiki.project1999.com/Category:Classic_Era
http://wiki.project1999.com/Players:Pre_Planar_Gear
http://wiki.project1999.com/Patch_Notes
http://wiki.project1999.com/Special:MultiCategorySearch