I'm not sure where you can read up on the layout of a bootable CD. I would presume that it has a standard MBR which points to a "boot record", etc. Down at the BIOS level it dosen't make much sense to me for it to have extremely different code. I would presume that the lowest level sector read & write routines would need to be specific to the media, but once you are past that point everything else should mesh.
I don't know about the FC5 #1 disc, but I do know that both the FC3 and FC4 #1 discs boot fine. I have burned and used them.