What Mehtab Singh has written is correct although perhaps the wording he has used has confused people - compositions such as "Jit Dar Lakh Mohamda", "Raag Ramkali Ratanmala" and "Hakikat Rah Mukam Raja Shivnab Ki" are inauthentic writings which have been added at the end of old handwritten Saroops of Guru Granth Sahib, usually after Mundavani.
Such inauthentic writings have been in circulation even since the time of Guru Sahib as Mehtab Singh's link points out with regards to the Banno Bir. "Jit Dar Lakh Mohamda" appears in some old Janamsakhia but does not appear as often in old Saroops as other compositions such as "Raag Ramkali Ratanmala" and "Hakikat Rah Mukam Raja Shivnab Ki".
When Guru Granth Sahib was standardized in the 20th century by the SGPC, the many variations in minor spellings/wordings, the number of Angs, and various other issues such as this were studied, so that one single copy of Guru Granth Sahib could be printed without there being differences in printed Saroops. At this point, the above compositions were removed.
There is still some disagreement on certain spellings of words, and if Raagmala should have been removed along with the above compositions, but all and for the most part there is agreement on the modern printed Saroop of Guru Granth Sahib.