You are definitely on track there. I came to the same conclusion. Reverend J.J. Watts of Phelps County, Missouri recorded family histories by the dozens in the mid-1800s and wrote about Bill Wilson:
William Wilson, born Oct. 28th 1837, was killed (shot) in Grayson Co. Texas near Mantina Jan. 24th 1869 for his money. Aged 31 years 2 ms. & 26 days.
The name is spelled differently but I'm sure it is referring to the same place.