This is the earliest western shirt pattern I've found thus far. Unlike some of the later western shirt patterns, this is purely a fancy dress shirt - no workaday checks or stripes are illustrated here. Note the spectacular embroidered cuffs on Mr. A's shirt.
McCall was based in New York City, and I suspect their illustrators were mostly local talent, so their knowledge of cowboys may be based almost entirely on the oaters they took in at the Saturday matinees. Any Saturday would do; between 1943 and 1947, almost 500 westerns were released in the United States, starring the likes of John Wayne, Randolph Scott, Joel McCrae, Roy Rogers; even Errol Flynn and Robert Mitchum did their time in a Stetson during these years. (Mr. B. would appear to be related to both Randolph Scott and John Wayne.)
|A few of Roy Rogers's costume changes, courtesy of LIFE magazine|