If that number is appearing on the frame, as I suspicion it is, that is the serial number and not the model number. The model information appears on the barrel and will be something similar to 101.1. In any event, these single-shot shotguns top out at $75. sales@countrygunsmith.net
1949
$450.00
Nothing much. Single shot, 20 gauge, and "Sears and Roebuck" on it (it was probably made by Savage) all work against it having a high value. It may be worth $40-$50 to someone.
410 is not a gauge. 410ga
The value of a 12 gauge Sears and Roebuck single shot bolt action model 14 will vary depending on the condition. If the gun is in good condition, it could be worth $150-$200 dollars.
http://www.e-gunparts.com
about $100
Winchester
I believe that your Sears shotgun is a Winchester model 37A shotgun that was made for Sears Roebuck And Co,.
It depends on the the number of barrels, year, model, condition and serial number.
about $100
The value of a Sears Roebuck 12-gauge 101.100A shotgun is around $100. This depends on the the condition of the firearm.