I think my question is answered on Fantha Tracks: https://www.fanthatracks.com/news/collecting/there-were-three-take-a-look-at-the-three-vintage-era-palitoy-and-kenner-battle-damaged-x-wing-fighters/
The 1978 date stamp is still odd though.
I have a very similar find. Its the Kenner mould of the X-wing with battle damaged stickers applied and stamped 1978. There are two notable differences to the example given by MotoXWing287 and examples given above. Firstly, there is no light on the nose cone and secondly the battery cover opens...