If yours is an SE model, as shown under your listing, and it's a W212 model, then they had halogen lights as std. IIRC, however, the intelligent lights were optional. You should be able to change the parking light bulbs on a halogen-equipped car and it's usually explained in the handbook
If you're not sure how to tell, I'm fairly sure that the halogen cars have an orange filament-type bulb as the indicator, whereas the others have what look like stepped leds as indicators. I'm not 100% sure, though, as I don't have one.
It wouldn't hurt to replace both, and I'd suggest buying decent brand ones as there are loads of cheap bulbs about that don't last very long, ie the remaining original bulb might still last longer than a cheap new one.