The Greek Military single trigger assembly will fit the commercial '03 M/S.

The Greek Military trigger guard bow & trigger plate is also needed when using the above Military trigger as it is cut for the single, 2 stage trigger.

The Military trigger guard bow has the same notch and lip at the front edge that locks it to the rear of the magazine frame of the rec'vr as does the commercial DS trigger plate assembly.
The rear guard screw hole is in the same position and takes the same screw as the commercial unit.

I have found that some of the Military guard & bow trigger plates are a bit wider than the commercial DST unit and may need some additional inletting. Some not.

Some find the Military TG guard bow unnecessarily large in size. I guess you could live with it or do some metalsmithing and cut and weld to reduce it's size.
The Military single trigger does end up positioned in the middle of the bow,, necessary as it is a 2 stage pull and it needs the extra length behind it to complete that 2 stage pull.
You can heat and bend the lower portion of the trigger and reposition it slightly to the rear of the bow for a better look,,there is a some room for that. But really, the single trigger is in nearly the same position as the front trigger of the DST unit. It just looks off on it's own w/o a set trigger taking up any room behind it.

The original shotgun style trigger guard of the DST unit can be fitted to the Military guard plate after removing the bow. But some careful work is required as a deep cut is made behind the trigger opening slot to reduce weight of the unit and you have to be carefull not to file too far there. But it can be done. Also, the front of the guard is a hook,not a screw fitting, so that takes a bit of extra care in fitting too.