all that info given there is simply census. It doesn't mean that Fehring did not leave for a short time and come back. He may have married 1873. Regardless of census information. one doesn't always give the correct year especially when your thinking one thing and the census taker is thinking something else. Perhaps he went east tosee others and decided to take a wife. He could have married there in Montana then again not. Also census gives Mary's age different twice. one says oct 1847. another time says she is age 52. the immigration may not be taken as word of god either.
I don't want it to be.lol I hope to find siblings. in the emsbuhren site it gives hints of more family. So I will have to pursue it. and see if any of the Garrison family have info there in Montana.