Were they cryo-vac packed with a solution? Or, fresh cut/packaged ribs?
If cryo-vac packed, they will feel a bit slippery, but if you rinse them off with clear fresh water and smell them, you will know if they have gone bad. The odor will be somewhat off from the norm...if they are definately trash can material, the odor will be rather offensive, so take it slow.
Hope you come out allright, good luck!