Bellmore Gun Co was a store-brand manufactured by Crescent. I don't know what you mean by the "code".
Made by Crescent Fire Arms Co, 1893-1932. Worth $150-$250 depending on condition.
Probably.
50-100 USD
404019
Try gunstocksinc.com
try gunstock inc. they have them
try e-gunparts.com
In reproduction catalogs from Sears @ turn of the century
try gunstocks inc
Any of the current stock makers should be able to help you.
AFAIK, there is no published sn data on Crescent Arms.
Double barrel?? Single shot?? More info. is needed.