Thanks for the input. I have a right wing side extension now and a table. My wing extension table is supported with a steel frame tied to the saw, so a back fence rail isnt needed to support the wing extension.

I currently have an old (1st generation) Excalibur Fence with 50€� rip. I am asking about the back rail because I want to build an outfeed table with a dust collection system underneath. I would like to build the outfeed table so it can be butted flush to the saw table with no gap. To do this I will need to change my current fence which isnt great (because it has the old c channel rails). It seems to me from looking online that an accufence doesnt really need a back rail to function. I was hoping to hear from anyone using an Accufence, Jet Exacta, or Beys w/o a back rail. Sorry for the confusion.