Just taking a WAG ! My guess it is 3.5 lb. double bit. After a good brushing with an angle grinder or a two day soak in vinegar you may find a makers mark on it. Rust yes, but it doesn't appear to be deeply pitted. As it is not identified, it's worth $5 to $10 bucks without a handle. You can find a new Council Tool d-bit for around $59.
It could be a diamond in the ruff or a very common double bit. I say it can be restored.
Watch Ebay for a nicer one with a handle..you should be able to find one for $30 in better condition.