Looks nice. Tru-Oil, however, is no better or worse than any other common wiping varnish - just more expensive. Basic ingredients are polyurethane, a polymerized vegetable oil of some kind (linseed, tung, walnut, etc.), and mineral spirits mixed in equal parts or nearly equal parts, depending on how thinned you want. It's also known as Danish Oil - which has nothing to do with the Netherlands, btw.
That said nearly any finish, including natural varnishes, shellac, etc. will preserve the wood for literally centuries as long as it's kept out of temp and humidity extremes, and away from a variety of wood eating insects and fungi. Your Dad's care of it is a significant factor in how it has remained in such good condition. If he'd left it hanging in the back window of his pickup truck for those years, I guarantee it wouldn't look like that now.
