Rare Sks? Identify factory code

[pc9]

Picked this up a few months ago from a online auction.
I don’t recognize this factory code and it has a flush fit mag
All numbers match
Is it rare?
What would be the value?
Thanks for any info

 

[tinviper]

6665?

 

[Curtton]

6665?

http://www.sksboards.com/smf/index.php?topic=11063.0

you are close but its 6656, i had to look it up.