Employer-sponsored plan contributions are reported on your W2, Box 12, usually with code "D" or "E." Box 1 of your W2 should be reduced by the amount of your contribution (unless it's a Roth 401k). This has the same effect as a tax deduction, so no further reported is needed.
Your existing Rollover IRA does not need to be reported, unless you contributed to it or withdrew from it. This is true for all retirement accounts- only report contributions, withdrawals, and rollovers. But in the case of employer plans, it is already accounted for on your W2.
