A silver color metal and enamel device 1 1/8 inches (2.86 cm) in height overall, consisting of a silver Philippine sun on a light blue background above a red heraldic chess rook surmounting two horizontal wavy blue bands and all beneath and between a red scroll, arched at top, the ends curving upward and terminating at the upper corners of the blue wavy bands inscribed "HOMINES SUPRA ACTIONEM" (People Then Action) in silver letters.
Dark blue and scarlet are the colors traditionally associated with the Adjutant General's Corps. The organization's World War II service in the Philippines and the award of a Philippine Presidential Unit Citation are symbolized by the colors blue, white and red, and the sun adapted from the Philippine flag. The two other campaigns during that period, New Guinea and Leyte, are represented by the two wavy blue bands alluding to water and referring to the Pacific Theater. The chess rook refers to the ability to maneuver on the battlefield and to the unit's service as a Replacement Battalion during World War II. Symbolically the chess rook can also apply to the organization's current mission in the area of personnel.
The distinctive unit insignia was originally approved for the 387th Personnel and Administration Battalion on 8 July 1977. It was redesignated for the 387th Replacement Battalion with description and symbolism revised on 19 October 1990.