According to Apple, Mac OS X installs are not hardware-specific. However, the recommendation for system administrators is to always install on the newest machine the build will be used on. (Remember, also, that pretty much all the Macs that officially support OS X are "UMA" machines -- Unified Motherboard Architecture -- which means that they use the same basic software. OS X installs it all, since every machine it installs on has similar software requirements.)
Mac OS 9 easy installs are hardware-specific, but by doing a manual installation, you can just add on the laptop-specific control panels and extensions. A laptop will boot just fine without the extra stuff, though. It just isn't an optimal install.
tooki