If you have the ability to scan at higher resolution...I would. I've restored a few old WWII photos of my grandfather - some were yellowed, creased, and spotted wallet-sized photos which I was able to clean up and make quite reputable 8x10s out of. The key was being able to scan at the absolute highest resolution you can - this allows you to clone out spots, creases, etc, work on color blending, and clean up edges and contrast lines at extremely high res (very large size), then reduce the size of the photo to a normal printable resolution and apply USM. The downsizing from a higher res will seriously improve your results in the final saved version, both sharpening the overall results, cleaning up the focus a bit, and reducing the scars from your editing, and will allow you to apply more USM for sharper effect without getting white halos around the edges.