V3のHead と M3のHead は頂点数が違うらしい。
seisui さんの Blog より http://www.doblog.com/weblog/myblog/30898/2622812#2622812
# -----V3-----------------------------------------------------
# InternalName: head:3
# ExternalName: Head
# Num verts: 38284
# Num sets: 151400
# Num elems: 38342
# Num tverts: 39655
# Num tsets: 151400
# Num tElems: 38342
# -----M3-----------------------------------------------------
# InternalName: head:2
# ExternalName: Head
# Num verts: 38290
# Num sets: 151442
# Num elems: 38354
# Num tverts: 39661
# Num tsets: 151442
# Num tElems: 38354