1968 to 1970 NOS gas tank or a mint used one

I have a brand new one that isn't NOS or stock. It fits perfectly (Gonna swap to FI and get a FI ready tank) Why does it need to NOS? You won't know the difference by looking at it if you are concerned with the restoration piece of it.
gotta tell ya on a OE GOLD type resto, OE NOS or mint used is the only way to go all aftermarket parts(no matter where they come from) have minor sometimes MAJOR differences than OE.