The problem has been that if an instruction manual is made for 1 particular GPS, it may not apply to others. I believe it was decided quite some time ago not to proceed, at least not from RevEd.
The challenge was open for any contributor to write one if they so wished. But again, where do you start?
Feel free to ask questions as quite a few of us have prior knowledge of working with various GPS modules.
Was there anything specific you needed to know?