The SL/E certainly had 4 speakers, it was the first commodore to do so.
2 in the dash (1 in each corner) and 2 on the rear shelf.
The other hassle with the SL/E is you cannot use the factory wiring at the headunit for the speakers, only the power, as the speakers were powered by an external amp mounted to the driver's kick panel/pillar area above the bonnet release lever, and it was only line-level signal sent from the head unit to the amp.