Nice catch.
Looks possibly unissued, straight to long term storage. Does it have crossbolt stamps on both sides of the stock?
From the evidence I've seen, the gold bayonet is not an original trait. It is likely a, quick drying, yellow chromate conversion coating (dip) applied during long term storage as corrosion prevention.
Early Chinese production was a defacto third soviet production line-- soviet made machinery and under the direct supervision of soviet technical advisors. For all intents and purposes the early chinese sks is an exact copy of the final soviet sks design-- and there is no evidence of the golden bayonets anywhere among the contemporaneous Chinese guns. Nor for that matter is it seen on the contemporaneous Romanian guns.