Earlier, also namdharis were khalsa, and today as well they are Khalsa. Dalip Singh never preached that he'll convert namdharis into khalsa. Though he narrow down the distance by preaching them to wear kirpan and greet each other with fateh "waheguru ji ka Khalsa waheguru ji ki Fateh". Also, he made namdharis to do sewa at Annadpur Sahib , Pounta Sahib and Patna Sahib. What more is needed? Lastly, please clarify us the definition of khalsa as described by Guru Granth Sahib ji.