The drive on the front would be a caddy loading CD-ROM drive, most likely an AppleCD 300, which is a 2x CD-ROM drive. You can either find a caddy for it and use it, or you can swap it out for a tray loading CD-ROM drive. However, if you swap the drive out, you'll need to either remove the caddy loading bezel and either have no bezel, or replace it with a tray loading bezel (which can be sourced from a Power Mac 7100).