Shotguns by that name were manufactured by both J Stevens and Crescent. A gunsmith should be able to produce/remanufacture any part you might need.
it is a Stevens, parts are interchangeable...
Try your local gunsmith. The Riverside is a Stevens shotgun. If you can find out which model it is, you can probably find the wood at Numrich Gunparts
Buy my 20 g companion,and there are your parts?wjw2010@live.com
Depending on which parts, they may need to be made.
A FEW parts are available from gunpartscorp website.
Numrich Arms should have them.
The 238 is similar to the 258. For parts, try gunpartscorp.com
i found a small list of parts at numrich guns and parts
Where can you find parts for your Charles daily shotgun
numrich arms - do a web search for them, they have a lot of stuff....
Gun parts Numrich Arms West Hurley New York. Or, we have them. sales@countrygunsmith.net
Go to gunparts.com "Numrich" they have new & used parts