OK
What I mean by that is the whole electrical assembly (scratchplate, pickups, wiring, pots, etc) has been taken out of a 1983 SilverStar and put into the 1979 body you have there.
It is very easy to do and is more common than you think.
On the up side, it is still all genuine SilverStar - just from 2 different years.
Oh yeah - the body code 9=2&3 YS (and it should have a matching neck code also of 9=2&3 ) means a September build, production run 2 and 3. As stated before YS means Yellow Sunburst (3-tone sunburst)
Peter Mac