Spelling of names is only important to people of the present day. We take great notice of how a name is spelled. In the 1860's you will not find a record of a name change, unless it is a divorced woman, taking back her maiden name. If you pay attention to spelling and do not research all variations of how your name could be spelled, you are missing the boat. Adding an extra M is not a big change. Sometimes people dropped endings or "Van" or "De" before a surname. In my own Spalding family, a man was released from WW I and they spelled his name Spaulding. Do you think he waited for the paper work to be changed? It would have delayed his getting out of the service, so to this day, his descendants spell their name Spaulding. Yet, they are as close as first cousins. A young person born out of wedlock will be listed with one surname in one census, then with a totally new surname in the next census, and they have never gone to court. . . In the 1800's people took in children, but never went to court to adopt them. I have seen one formal adoption in a deed record in the 1880's. Two Matlock families lived near each other and they kept getting their mail mixed up. So, one decided to become Medlock instead of Matlock. This is a true story.