This large format catalog, distributed to major gun shops, introduced the Model 21 20-Gauge 3-Inch Magnum and featured a full page devoted to the Custom Built .410 Bore.  Supplemental price lists were issued until the beginning of the 'Custom Shop Era'.

20 Gauge Magnum

 
The typeset, found in the ruins of Winchester's Custom Shop, was made from the master used to print this page.  It is hard to see in the scans, but the grain in the butt stock does match.

World's Finest

Double Barrel Shotgun

Field Gun

Magnum Duck Gun

Custom Built .410