GM Fu here is referring to the similarities between the 1848 version of SLT, and not the general SNT that is more common today.
Things have changed since then obviously as evolution occurred. What this proves is that at the time of 1848 Red Boats, the practice of SLT was done with the Emei technology
My reading of this is:
1. The SLT kuit is preserved from the Red Boat era. The kuit describes SLT content and practice at that time.
2. GM Fu has gone through it line by line and found to a large degree it matches almost word for word the same as his own writing.
3. As a result, SLT practice at the time of 1848 on the Red Boats contains Emei technology