SB Cam Thrust Plate P5249637 no longer made? Only tensioner now?

But is it not the cam gear that prevent the cam from walking the other direction.?
I am out of my league here but doesn't the cupped washer on the cam bolt control the movement as well. When I tore down my motor, someone must have lost it and used a flat washer. Cam had crazy in /out play until I replaced it with proper washer then play was in spec. somehow cam was unaffected.