I wish I could help u more, however I am unable to at this point in time.Your Charles Kehr, would have been Carl Kehr.
I believe my Kehr ancestors were all related.And it is possible that some went to USA since I know that other relatives from Eisenach took the boat trip to New York, and I have found them listed in the records found online at www.Ellisisland.org
to recap again - my KEHR realted names are as follows.
JOHANN GEORG KEHR (B. @ 1717?) his daughter ANNA MARIAKEHR,(m. 31/10/1765 JOH. GEORG CHRISTOPH HAHN) Christian Carl KEHR (living @ 1767 sister of Anna Maria?) Michael Adam KEHR(B. @ 1742? IN EISENACH?) his daughter SOPHIA FREDERIEKE KEHR (b 17.8.1777 IN eisenach) (m 15/08/1799 JOH. CARL CHRIST. HAHN (d 27.12.1844 age of 68)