I am in the process of updating a cemetery burial database with information I obtained from researching the Otto Schemansky & Sons Monument Co list of sales over the past 100 years.
One of the listings was for a Mrs Nelk who lived on leland Street in Detroit purchased a headstone for her husband Jozef Nelk in late 1907 or early 1908. The headstone was inscribed with his name, dob 19 Mar 1838 and dod 27 Dec 1907 and delivered to Sacred Heart of St Mary Cemetery in Detroit.
As the Project Manager for the Polish Genealogical Society of Michigan for this cemetery, I have not seen this headstone nor the name Nelk amongst the burials.
Later Mrs Nelk purchased a cement "box" (vault) to be delivered to the cemetery.