I've owned several 20" 1640s that are all original, and handled dozens more. Check gunbroker, gunsinternational, and gunsamerica--you'll see a lot of them. Most of them came in a very trim walnut stock with a Schnable fore end.
20" is kinda short for a .270 but as others have pointed out, either the action or the stock are worth close to the asking price.
Okie John
