It is semantics. Because there are specific negative implications that apply the to term 'commercial'.
The only guns known to have been made specifically for the commercial market are the modified variants (ak mags, scopes, short barrel, etc), and the post 1987, standard configuration guns (serial prefixed 88-94). But all of these guns were cobbled together from leftover parts produced for military/security purposes over nearly thirty years of type56 production in China.
The fact that the op rifle bears a triangular military arsenal stamp as well as the 56type designation are more than enough indication that it is a military rifle (issued or not) that ended up on the commercial market.
Made by Norinco is a misnomer. As the only guns Norinco might have had a part in "making" are the modified guns and post 1987 standard configuration guns, which, as already stated, were assembled from leftover mil-spec parts.
I stressed the "not commercial" notion, not to be confrontational or contrary, but because of the negative implications that the term 'commercial' has regarding quality of build, function, and overall reliability.
Many claim unjustifiably that all of the Chinese sks's are of poor quality and unreliable. But it is not true.
However, there is a nugget of truth to the claim, because the truly commercial guns -- i.e. the modified ak mag variants-- have a documented history of unreliability in feeding and function and overall magazine fit and compatibility.
Despite the fact that this reputation only applies to a limited population of the truly "commercial" guns, it has also been mistakenly assumed by many that it applies to the standard configuration guns. Which is patently false.
Without seeing the op's entire rifle, it may seem difficult to tell what kind of rifle he has -- commercial or mil-spec. But the fact that the rifle still bears the triangle arsenal stamp and the "56type" (五六式) designation indicates that it was manufactured as a mil-spec rifle. As most commercial guns have had the arsenal stamps scrubbed, and the "56type" designation was omitted on every gun assembled after 1984.