from what i have researched it was made by savage. the savage model number for it is 96/96y i have seen them priced any where from $70 at 75% condition to 120 at 95% condition.
I believe that your Sears shotgun is a Winchester model 37A shotgun that was made for Sears Roebuck And Co,.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf
Try e-gunparts/used to be called Numrich arms/It's on the web
sears roebuck and company
Its a Sears branded Mossberg 500.
The value of a Sears and Roebuck 12 gauge shotgun model number 281512651 depends on its condition. This gun in excellent condition is valued between 100.00 and 135.00 as of 2014.
1952 by High Standard for sears& Roebuck
Winchester 1200
$49.95
410 is not a gauge. 410ga
Sears Slug Model 446.511761 is a Mossberg 500. All parts interchange.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf