The tombstone in the find-a-grave page is new. This introduces the possibility that it could either be a transcription error based on a damaged/worn stone, or possibly some sort of error by a descendant who ordered the stone...then again maybe the original was wrong. He lived long enough that errors would have been easier to miss during the period of his burial.

The creator of the find-a-grave page (great grandson) might be able to help you sort this out.