You can research the archives yourself for more specific comments, but in general Kohler parts are frequently not carried in stores because they have so many. Also, when you order parts from Kohler, you may have to wait weeks for them to reach you. Many of their parts are obsolete and no longer available, but even when found, the price for some of them is more than a quality new toilet. Try to convince your mom that pastel colors are no long in vogue and exact matching would be difficult or even impossible. I wish you luck.