Are you sure it is a lower rail? The single rail on the right bank and one of the rails on the left bank are long, much longer than the short rail on the left bank. Could possibly be an end from the long rail.
As I recall, the rails should almost touch the cam sprocket, not have a large gap there. Take a closer look.
see how close the upper rail comes to the sprocket. Looks pretty much the same on the other side, except there is only one rail.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.