If the employer provides a pension (defined benefit) plan, she is covered, even if she is not yet vested in the pension plan. Otherwise, with no employer-provided retirement account in her name, she is not covered. If the employer marked Box 13 Retirement plan inappropriately and will not provide a correction, you'll need to enter the W-2 without marking this box in TurboTax and include an explanation statement with your mailed tax return.
If you've already done this and the IRS is questioning her deduction for a traditional IRA contribution, you'll need to provide information to the IRS to substantiate that the employer marked box 13 inappropriately. That would be information describing the employer's retirement plans, not a quotation from IRS Pub 590-A. You need to establish that the employer, not the IRS, has made a mistake.
