$700 +\- $50 if the rest of the rifle is in great shape. The rifles without a safety are more desired than those with from my reading. What is the model? There were a bunch of 336 models made. PS …. There are stock's available on eBay and occasionally on MarlinOwners.com
You can look at what actually sold on Gun Broker. You can buy those in very good shape or $600 to $700, some with scratches or blemishes in the bluing in the $500's. I think one with a cracked stocked would bring less than that if it even sold.