I'm sure the zip ties keeping the air cleaner together aren't from the factory.

Seriously, if threre's no ALDA on the IP and no overboost protection solenoid then I'm sure it's not a factory set-up.

Just the fact that no one's mentioned such a factory set-up in this forum is reason enough to be sure it's an add-on.

Sixto
91 300SE
87 300SDL
83 300SD