Yes, those calcs are correct. 2 N-m at the motor will produce 476 N at the rack if zero losses. 85% overall efficiency is probably typical, so about 400 N.
Also keep in mind (assuming it's a stepper motor), to reliably not lose steps, most industry sources recommend an extra 30-50% of torque available, all the way to the specified top speed. So, the numbers you describe would have a ~100% torque margin--plenty safe, or you could accelerate faster if wanted.