I checkd 3 large databases for cross reference of the original makers of firearms sold by Sears (JC Higgins was their house brand) None of the 3 show a model 40 rifle. Can you please recheck markings, and repost? An experienced gunsmith can probably identify make from the appearance.
Proofhouse.com has a store brand chart. When you find out who made it a value can be estimated.
Which model??
We have parts for that model. gunshop@nctv.com
That model is obsolete, but we have a good selection of parts. sales@countrygunsmith.net
Try e-gunparts.com
Egunparts
Numrich Arms is a good source for gun parts.
Go to Numrich Gun Parts Corp.
The J.C. Higgins Model 103.13 .22 caliber rifle was manufactured by the High Standard Manufacturing Company for Sears, Roebuck and Co. in the mid-20th century. For a replacement buttplate, you can check online retailers specializing in gun parts, such as Numrich Gun Parts, Brownells, or eBay, where vintage firearm parts are often available. Additionally, you might find buttplates through specialty shops that focus on vintage firearms or custom gun smiths.
Check with a gunsmith, or find the model number of your rifle, and check on line parts supply houses, like gunpartscorp.com
The Sears Model 42DL .22 caliber rifle was manufactured by Marlin Firearms, their Model 80. Check with Marlin for parts availability.
Try gunpartscorp website. They have a cross reference to find the make and model of your Sears shotgun.