If it's an Intel MBP, you'll be outta luck anyhow. Were there G4 Pros?

Yes, there were lots of G4 towers, the last gen had dual processors.

You'll be safer with the Universal dvd installs, which were retail units, not the machine specific ones that came with a mac.

I found an old leopard install disk, I don't remember which mac I bought it for but I assume it will still work on a G4. If you pm or email your mailing address I will send it to you, I'm not running leopard on any of my macs so I don't need it.