I would go to the Store Brand Cross-Over List in the back of the Blue Book of Gun Values. This list is also available online at several firearms related sites.
Stamped on the receiver and probably the barrels, too.
A Sears Mod 53 is a Winchester Mod 70. If Sears doesn't have an owner's manual for the 53 (and you can't find one on eBay), go here http://www.stevespages.com/page7b.htm for a Winchester manual.
Start with Winchester Customer Service. Winchester has made THOUSANDS of different models, and we would need to know which model to offer more help. Sort of like where to find a manual for a Ford truck.
The Sears 200 series = Winchester 1200. Parts should be available from e-gunparts.com if you can't find them locally.
The sears model 6c-22 was made Winchester/ same as Winchester model#490
That's one of the Canadian-built Winchester/Cooey models as made for Sears. We have some parts available. Please send a digital picture so we can properly identify the exact model you have. sales@countrygunsmith.net
The 282 is the Winchester model 521 made for sears
These were sold by Sears and Roebuck. The Model 300 is really a Winchester model 1400. SORT OF The Ted Williams 300 is basically a Winchester 1400, and the TW 200 is basically the Winchester 1200, but certain parts do NOT interchange. The buttstocks and trigger guards, for example. Here is a cross reference chart. It is correct that Sears had some exclusive features on the Ted Williams models. I have a Ted Williams 300 that has an adjustable choke that was not available on the Winchester 1400, for example. http://proofhouse.com/cm/house_brand.htm
Sears 200 series = Winchester 1200. Parts should be available from e-gunparts.com if you can't find them locally.
http://en.allexperts.com/q/Guns-Firearms-Projectile-1501/Sears-54-Winchester-94.htm
Daisy made about 50 thousand of the "Winchester 73" model ( it's really a Cowboy 1894) BB Rifle for Sears from 1969-73.
The Sears Model 1 may be a Winchester mod 121. L0ok there