We claim the ornamental design for a impression coping, as shown and described.
FIG. 1 is a perspective view of an impression coping, showing the new design;
FIG. 2 is a front elevational view thereof, the rear elevational view, left-side elevational view, and right-side elevational view all being a mirror image thereof;
FIG. 3 is a top plan view thereof; and,
FIG. 4 is a bottom plan view thereof.
The broken lines in FIG. 4 depict environmental matter and form no part of the claimed design.