Just look for one with a nice looking walnut stock, with no checkering whatsoever, and no cross-bolt safety. You don't need one in "Excellent" condition. VG+ condition will be fine.
I would only pay $300 to $350, depending the condition, the gunshow, and the time of the year.
Happily, there always thousands and thousands of 336s for sale, and you will be able to look at lots of them.
The ones made in the 1950s had a heavier, blockier, front stock. Whether you like those or not is a matter of personal taste. It is hard to find those in really good condition though.
Hope this helps.
Mannyrock