Vtg Plaid L Wool Gripper Pearl Snap Elbow Patch Western Shirt No Tag Pendleton? Suspect it is based on look, feel, location (porltand OR), gripper snaps,  and that you can see where the tag would have been and it is the correct size outline. 


Measurements

Pit to Pit: 24"
Pit to cuff end: 20"
Shoulder to bottom hem: 29.5

I am a large and it fits me pretty well.

See photos.