The Lombards have either a 333Mhz G3 or a 400Mhz G3. I seem to remember that the Powerlogix upgrade card for the Lombard, the BlueChip LS G4, which is a 500MHz G4 that completely replaces the old G3 processor, sometimes gave erroneous readings for the CPU speed and type. And here comes a word of warning. If it is indeed an upgraded Lombard, be prepared for trouble. They had enormous problems with overheating and not being able to use more than 256MB ram. You can check this by opening up the keyboard (two latches at the back of the keyboard), unsrewing the metal plate that covers the RAM etc and looking at what is in it.
If it's a normal G3 then just screw everything back in, install Panther and have fun .I have on my Lombard and it runs just fine, if very slow, but that's ok for me because I only use the terminal on that machine.
My advice with a Lombard is that unless you do more than browse the net and read mail on it, OSX is not really going to be your friend there. OS9 is much better for it.