Need help identifying bike

[shermerrr]

I've picked up what I assume is a late 70's XS500 from my brother. The number listed on the engine is 1J3-200300. Based on the 1J3 this could either be a '76,'77, or a '78. Does anyone know the exact year?

Thanks,

Austin

[Airhead]

I make it XS500F 1978 Austin.