If you are asking if it's possible for the camshaft timing gear to have its hash mark in the wrong place (180 degrees out) I suppose that may be (I've never seen that). When the hash marks on the cam and crank gears are aligned opposing each other the engine will be at TDC for #4 cylinder on the compression stroke. #1 cylinder will be at TDC also--but on the exhaust stroke.
Industry wide having what we (modern North Americans) consider to be the #1 cylinder as reference point for engine assembly is not necessarily true everywhere. Most engines in French cars count #1 to be the cylinder closest to the flywheel. Volvo's numbering system calling the forward most cylinder #1 but using #4 as a reference point is confusing but as long as the tech doing the job knows this there should not be any problem. With the marks aligned the distributor should point to #4 cylinder. The tech can commence doing a valve adjustment (if the cam has been changed) starting with #4 - then #2 - then #1 - then #3 rotating the motor the appropriate amount for each. -- Dave