I guess Wm is Wilhelm. Johann and wife Rosine came to New York from Gerlingen, around Stuttgart, in 1853 with sons Karl, Gustav, Wilhelm and Adolph. Sons George John and John Christian, and other siblings were born in New Jersey. George John's son George Henry was my grandfather. John Christian went into the banking and brokering business in NJ and NY.
Do you have Wilhelm's date of birth or anything. Do you know where in Germany? Please email. I don't post or look here very often.