Amulets of the Khonsu emblem without a plinth, but with a protrusion and a suspension loop are also rare1, in carnelian, and undated

Carnelian, protrusion broken
L 1.5, W 1.2 Undated
Museum of Fine Arts Budapest #51.1564

Carnelian L 1.6, W 1.3, T 1.0 
Undated © 2012 Musée du Louvre/Antiquités égyptiennes
#N 4648

References

1None, Unpublished amulet