Man, it's been a real long time.....
IIRC the protruding ends of the rods that are threaded have a teeny tiny hex on them. With the headlight installed and the clips also installed, the one on the end moves the headlight horizontally, and the one on the top middle moves the light vertically. Sometimes those black plastic round holders that the clips grab onto get stripped. Then there will be no adjustment. It is the black plastic part being held stationary by the clips and the threaded center of those plastic parts that makes the adjustment.
Sorry if this makes no sense.......

Basically yes they are adjustment screws but is is the position of the black plastic part on that threaded rod that makes the adjustment. Try threading the black plastic part in or out, and then installing the headlight. Then you can turn that tiny hex on the protruding end of the threaded rod to fine tune it into position.