Well, while the Chinese began making their version of the SKS in 1956 (that's why it's called a Type 56) Norinco (China North Industries) did not begin operations until 1980.
Many of their Type 56 carbines were imported in the early 90s by China Sports Incoporated (CSI) of Ontario, California. In 1993, further import of these rifles was blocked when China lost its favored nation trade status.
The markings for "Norinco" in Chinese would usually be 北方工业 or 北方工業. Do you have instructions on how to take it down, care for it, load it?
If not, see here: http://stevespages.com/pdf/sks_56.pdf
Now, you next question is going to be "How do you convert this to accept a removable magazine?" My answer is - Don't try it. They work very well with the factory fixed mag. 98 out of 100 that someone tries to fix up with a detachable mag does not work at all.
PLEASE remove and clean the bolt thoroughly before shooting. If the firing pin channel has congealed grease in it, can cause the firing pin to stick in the foward position, resulting in uncontrollable firing as soon as you let the bolt slam home.
Fun little carbines. Got my first one in 67.
BTW- PICTURES! We need PICTURES!
And welcome to the forum- see that you are a new guy here. Drop by the Intro thread and say hello, tell us a bit about yourself.