well, the answer isn't a simple yes or no.
if you still have the board up and running with its original bios, you can extract a lot of information from the running board without having access the the actual schematics. to the extend a lot of manufacturers used the chipset maker's advice on motherboard layout. so infact a lot of boards have a very very similar design. however they vary very much in details.
anyway: go and check coreboot
. there you'll find plenty of sourcecode for initializing motherboard components (and ways to configure it to make it work despite those differences).
If you email me include [WIMSBIOS] in the subject.