generally OS X installs are machine universal
but there are some edge cases (mainly on machines that shipped with an out going OS X version) where this is not the case, and you need the specific disks for that machine to get full driver support
another example would be Tiger on the GeForce 8600M GT Mid 2007 MBPs and Radeon 2400 XT/2600 Pro iMacs, even a fully updated 10.4.11 install does not contain the GPU drivers for those machines, luckily apple did put out a GPU driver update specifically for those machines, that if system update detects MBP3,1/iMac7,1 it will offer up those updates, but otherwise you dont get them
but there are some edge cases (mainly on machines that shipped with an out going OS X version) where this is not the case, and you need the specific disks for that machine to get full driver support
another example would be Tiger on the GeForce 8600M GT Mid 2007 MBPs and Radeon 2400 XT/2600 Pro iMacs, even a fully updated 10.4.11 install does not contain the GPU drivers for those machines, luckily apple did put out a GPU driver update specifically for those machines, that if system update detects MBP3,1/iMac7,1 it will offer up those updates, but otherwise you dont get them