My rifle is just the same as yours, except that the sideplates cover the cross-pin. It's interesting to see that the overhanging sear allowed the maker to have a much thinner tumbler, because the distance from the axis to the bent is much longer than for a regular A&D action. This much reduces the force inflicted by the main spring on the sear, and thereby the wear on it. The thinner tumbler means a thinner action slot, and therefore a stronger action. This type of side plate would not be possible on a typical A&D!
The ejector mechanism is also very interesting and is entirely located in the action. It is behind the cocking lever, on each side of the front lump.
Best regards,
WC-