I'd say the case is the same on the "DVI" 667Mhz, 800Mhz, 867Mhz, and 1Ghz TiBook models. The 400/500Mhz models some or all of the 550/667 models had an optical drive that wasn't standardized to what the later TiBooks and current AlBooks have and had different port layouts like the lack of DVI (if that's part of the case bottom).
Of course, if you find a working TiBook 800+Mhz don't just take the case from it. And if you do buy one you can preserve the case bottom by using a
Podium Coolpad or something similar...mine still looks great!
Voch