The engine number is of no help at all.
I'm prepared to wager that this is the real deal 1200 GX engine, not just a head plonked on a stock block & these are quite desirable in completely stock trim. The Webers are, .... for me, an abomination on this particular engine.

I ran a big bore 1200 GX in my 1000 sedan for well over a decade & for street duty they are the sweetest thing around. Those Hitachi's, when in good serviceable condition, provide flexibility, ecomomy & right peppy performance.
I absolutely loved mine.