So is it a Mark X??
If it is a mark X, it should have a sliding thumb safety.
Looking at the RH side (bolt side) of the rifle, and assuming the start of the trigger to be @ 6 0'clock:
Moving counter-clockwise-- @ 5 o'clock there should be a safety adjustment screw. @ 3 o'clock there should be a weight of pull adj. screw(with a nut).
Moving clockwise from 6 0'clock(the trigger)---there should be an overtravel adj. screw @ 7 o'clock(with a nut) and a sear adj. screw at about 9 o'clock(with a nut on it).
If it doesn't look like this, then it has an aftermarket trigger in it already......
