Assuming that's a threaded feedneck (pretty sure it is, not sure if those guns ever came with that particular feedneck stock, or if there's even a press-fit variant of it), the CCM cocker-threaded feednecks (called STO/Intimidator in their ebay store) will fit.
It is definitely a 2k millennium. If you are buying a complete frame then it makes no difference if it's a pre or post frame. The biggest difference would be the trigger plate if putting a frame together.
I will never go through a midlife crisis if I refuse to grow up.