rigifyoptimize

import bpy

bonelibrary = {}

for i in bpy.context.object.pose.bones:
    if i.custom_shape == None: continue
    OBJ = i.custom_shape
    DATA = i.custom_shape.data
    if bonelibrary.get(str(len(DATA.vertices))) == None:
        bonelibrary[str(len(DATA.vertices))] = {}
    COUNT = len(bonelibrary[str(len(DATA.vertices))])
    for item in bonelibrary[str(len(DATA.vertices))].items():
        if [DATA.vertices[r].co for r in range(min(3, len(item[1])))] == item[1]:
            i.custom_shape = bpy.data.objects[item[0]]
            break
    else:
        bonelibrary[str(len(DATA.vertices))][OBJ.name] = [DATA.vertices[r].co for r in range(min(3, len(DATA.vertices)))]