SKS Help

[CHSD]

Can anyone help me understand these number stamped on an sks? I've tried watching a bunch of videos and I am confused. I appreciate any insight you can give.

There is also a made in China stamped on the opposite side of the receiver. Not sure why I didn't get a picture of that.

 

[JREG19]

That should be the serial number. Originally all of those parts would've had the same number.