Completes major inhand split project (#2178)

code/game/objects/items/devices/instruments.dm

@@ -4,6 +4,8 @@
 	resistance_flags = FLAMMABLE
 	max_integrity = 100
 	icon = 'icons/obj/musician.dmi'
+	lefthand_file = 'icons/mob/inhands/equipment/instruments_lefthand.dmi'
+	righthand_file = 'icons/mob/inhands/equipment/instruments_righthand.dmi'
 	var/datum/song/handheld/song
 	var/instrumentId = "generic"
 	var/instrumentExt = "mid"
@@ -151,6 +153,8 @@
 	desc = "An exquisitely decorated bike horn, capable of honking in a variety of notes."
 	icon_state = "bike_horn"
 	item_state = "bike_horn"
+	lefthand_file = 'icons/mob/inhands/equipment/horns_lefthand.dmi'
+	righthand_file = 'icons/mob/inhands/equipment/horns_righthand.dmi'
 	attack_verb = list("beautifully honks")
 	instrumentId = "bikehorn"
 	instrumentExt = "ogg"