The ornamental design for the rear sight housing for a firearm, substantially as shown and described.
FIG. 1 is an upper left rear perspective view of the sight;
FIG. 2 is an upper left rear perspective view of the sight with an aperture for reference purposes;
FIG. 3 is an upper left front perspective view of the sight;
FIG. 4 is an upper left front perspective view of the sight with an aperture for reference purposes;
FIG. 5 is a back elevation view;
FIG. 6 is a front elevation view;
FIG. 7 is a right side elevation view; the left side is a mirror image of the right side;
FIG. 8 is a top view; and,
FIG. 9 is a bottom view.
The broken line disclosure shown in the drawings encompasses the non-claimed area of the firearm sight. The broken line disclosure is not included in the claimed design because that portion of the firearm sight may take different forms according to the type of mounting base used with the firearm sight.