From
http://www.thefiringline.com/forums/archive/index.php/t-45157.htmlThe Riverside double was mfg'd By J. Stevens Co. and is actually their Model 315. This is one of several utility shotguns Mfg'd by Stevens from 1877-1988.
There is a year code stamped on every Stevens double barrel shotgun produced between March 1949 and December 1968. The serial number is prefexed with a letter. If your shotgun does not have a letter preceeding the Sr# it was mfg'd prior to 1949.
In light of the previous damage to the stock, the Winchester AA Xtra-Lite 1 oz load would be a good choice for clay targets, dove, or quail and the Federal Game-Shok 1 oz Game Load 6s (available at Wal-Mart in AZ) for grouse or pheasant.
I hope the gun works out for you. If not, you might look for an honestly used but not abused Ithaca Lefever Nitro Special 12g.