The ones I remember being factory in the early days were on the front valance. Cars like the W202 C280 Sport or W210 E320 spec'ed with the AMG wheel/tyre/suspension package had a discreet badge in the centre of the front bumper at the bottom. Not on the boot lid though, although these tended to be added at PDI at the buyer's request.Im not sure it ever was factory fit to put AMG badges on a non-AMG car.
Sure, a dealership could do before handover if requested, but at the factory? I find that hard to believe.