Truth Stud Bracket; Attaches to casement window sash and operator arm attaches to the stud post. Arm is held in place with a metal Detach Clip 

Type: Clip On, Metal clip slides onto stud post
Handed: Yes, Right Hand
Truth Part # 12513
Markings: 40448 stamped on Left hand bracket, 40447 Right Hand. 
Sold : Each

Truth Snap On Stud Post 12510 LH / 12511 RH
Truth Clip On Stud Post 12512 LH / 12513 RH
The new style looks different, but works on many more applications - See additional pictures
The stud brackets came in 2 types 
1. Clip on has a metal clip that slides onto the stud
2. Snap On has a small ring around the stud and arms snaps on

Old Style Brackets:
Markings on Brackets: 40447 / 40448 Brassy color
Replaced: Wright hardware # 07867 / 07868 black color