FIG. 1 is a perspective view of an inside escutcheon plate assembly; FIG. 2 is a front view of FIG. 1; FIG. 3 is a back view of FIG. 1; FIG. 4 is a right-side view of FIG. 1; FIG. 5 is a left-side view of FIG. 1; FIG. 6 is a top view of FIG. 1; and, FIG. 7 is a bottom view of FIG. 1. The portions of the article in broken lines are shown for illustrative purposes only and form no part of the claimed design.