Q/ Any thoughts on whether/not it is real? In this case, 'real' would mean written by Iroquois, on a stone bought & paid for by Iroquois ...
Well, we know the memorial stone is real, as it is referred to as being located at "Fernleigh-Over", however, the words were not written by the Iroquois, rather they are attributed to the Rev. William Wilberforce Lord, D.D., former Rector of Christ Church, Cooperstown, NY.
The supplemental lines shown in the text below entitled "Morituri Te Salutamus" were written by the Rev. Dr. Walton W. Battershall, Rector of St. Peter's Church, Albany, NY (circa 1907).
More on the "Fernleigh-Over" Indian Burial Ground is recited here: