Things that could be easily changed included hardware, thick one ply pick guard, bell shaped TRC for a "squared bell" shaped MC TRC, pickups with 6 extra holes in back plates
(not MIJ), white rear cavity covers, rectangular profiled plastic (vs bone) nut.
Although the headstock shape differs from other early to mid 70's examples,
there is a pretty good chance it was produced by Matsumoku around that time.
If can post a pic of the control cavity with the white cover removed,
I can probably confirm who the manufacturer was.
Hopefully you can make something of this.