I'm a huge M70 fan, but I think the pre-64 market is way out of whack. I honestly don't even want one. They are exceptional guns especially for their time but with todays machining I don't think the prices are within reason.
I'd offer close to $500. That is what the action alone would be worth in pristine condition.
One last thing, you'd be surprised what it takes to make a pre-64 a collectors item. Any modification even the slightest and your rifle goes from high dollar to junk status. Things like sights, sight hoods, stocks, bedding etc...
Tom