Nice !

https://page.auctions.yahoo.co.jp/jp/auction/m237916682

Translated descrip,

Approximately 63 cm from the end of the nut to the center of the bridge
Medium scale (24.625 inch)
I think that it is MSG.

I think that it is 1979 because the number engraved on the finger plate starts from 79.

Hard case, dedicated power supply / DS5, 5pin cable is attached.

Very nice...the round battery plate is also indicative of around 79-80 (from what I've seen).