Yes. After the bios initialization, computer looks at the hda mbr if there is data.
If you launch again the installation, can't you directly select the Lilo option ? without reinstalling the rpm files (as far as I recall, one could choose that with Mandrake 9. I don't know if it's still possible with Mandrake 10 though).
Another thing you can do is go into the BIOS and ask the computer to boot with the second disk first (hdb).
There must be a lot of other solutions to directly put Lilo on the hda mbr but I'm also a newbee lol :)