The ornamental design for a guidetray for manufacturing dental implants' placement guide, as shown and described.
FIG. 1 is a perspective view of a guide tray for manufacturing dental implants' placement guide showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left-side elevation view thereof, the right-side view being a mirror image;
FIG. 5 is a top plan view there of; and,
FIG. 6 is a bottom plan view thereof.
The broken lines in the drawings depict portions of the guide tray for manufacturing dental implants' placement guide that form no part of the claimed design.