The ornamental design for a fenceposttop, as shown.
FIG. 1 is a perspective view of the fence post top showing my invention;
FIG. 2 is a bottom view of the same;
FIG. 3 is a top view of the same;
FIG. 4 is an enlarged side elevational view of the same; and
FIG. 5 is an enlarged side elevational view of the same, with this view
showing the fence post top as having been rotated approximately
45° from the view of FIG. 4.