Most likely not. If the employer has any brains, the actual liability will be only what you have EARNED (accrued) for January, i.e. 1/12 of 80 hours, plus any untaken vacation previously.
Pennsylvania law does not specifically require that vacation be paid out at termination. All the law requires is that the company adhere to its own policy regarding the issue. Does the company policy state that accrued vacation will be paid at termination?