I see now that the circuit diagram that you posted was drawn by someone other than the original maker. There are many errors in that diagram. Since the amplifier "worked" (illegally in the US CB band, I might add), the errors in the schematic must have been made by the guy tracing the schematic.
Just a few of the errors I spotted: The keying diodes are backwards. The high voltage diodes are backwards. D5 is backwards, The PiNetwork in the output is totally screwed up. The loading capacitor does nothing for SWR, etc, etc.