28 gauge..Both my cooey 37A's; one 12 gauge in Excellent plus condition and another one in .410 that is 100% factory production condition have no reference to winchester what so ever..They are marked cooey 37A, made in canada. The buttplate (Middle circle) ..where the winchester logo would normally be, is just blank. they are pretty much Identical to the win 37A's, except no reference to the winchester brand, only cooey..
The finish on the stocks, however, seems to be more "matte" and slightly "different" than those on the winchester versions.
My guess is that when winchester decided to begin production on the 37A's, they may have pondered as to what they would be put out as..and maybe put out numerous shotguns with just the cooey markings on them..
I know, sounds strange...but I have 2 of them..My guess is that they are quite rare. I had a chance on a 20 gauge as well but passed it up at the time..may still try and find it again.