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

No, not the cam gear... it is the thrust plate... which is why it is called that!

I just looked at my 340 trust plate and, despite the light surface rust, it looks like the wear is on the back, not the front, so I have it backwards. If so, then TMM is right, the thickness does not matter for the running cam location.