I replaced the fuel pump today as the old one was starting to make more noise than I felt comfortable with for an upcoming road trip. The old pump was 4 years old.
I purchased an Enduralast 43mm pump from EUROMOTOELECTRICS.COM. $114 with pump filter.
The anti rotating protrusion on the new pump was not located above the protruding ring as the old one was, but seemed to me to be useless, being located below the ring that prevents the pump from rising or sinking in the isolator. There is a notch in the top of the isolator that I think the protrusion sits in to keep the pump from rotating. Now I'm just guessing that this was the design and function.
Both pumps seemed to be a little loose in the isolator so I just cut up someone old fuel line and shimmed snug.
Charlie