Beware -- what Ancestry.com includes in its Findagrave index is from the main index that you get in the initial list when you search at Findagrave.com.
When you go to the individual detail page you will often discover that what was indexed was dates seemingly from death records, obituaries, genealogies, etc., not the exact gravestone reading. Often the person who created the memorial does not tell you what the dates, relationships, etc. were even from.
In addition some people just make stuff up about where people were buried, so you can't tell from just the index on Ancestry.com what exactly the particular entry is.
So consider the findagrave index on Ancestry.com to be a rather crude finding aid and do not save anything to your tree without viewing the whole findagrave.com entry. If no source is given for the stuff there, and if there is no photo by which you can compare the actual marker entry with the memorial's version, throw a few large handsful of salt into the mix.