That, or a little more, is what a 4" in good shape would go for around here. Grips would likely be beat-up rubber of some type.
If you want one, that's a square deal. It's stainless, so you can clean up the scratches and put new stocks on it. So you'll end up investing about $450 with tax and grips. Buuuuuut, the don't make them anymore. A new 64 is over $600 by comparison - and won't shoot .357.