Son William's marriage record lists her name as "Barbara Weber." Death record of step-son Christian Wurster lists her as "Barbrie."
Apparently it is the custom in Germany to give several names. These are not necessarily seen as "first" and "middle" names, but rather a series of names. One web site even suggests that the name given at baptism is often commonly adopted as the "first" name. The German records for her record er name as "Agnes Barbara" but since her son lists her as "Barbara" on his marriage certificate and since Christian Wurster's death record calls her "Barbie" I have chosen to list her as "Barbara Agnes." (ead)
The German baptism and marriage records are confusing as to Agnes. A baptism record lists her as the daughter of Johannes Weber and Marie Barbara Weber, being born January 1, 1819 and baptised January 2, 1819, in Freudenstadt, Wurttemberg, Germany. A marriage record for her marriage to Christien Wurster in 1840 (exact date not given) say the marriage took place in Ludwigsburg, Wurttemberg, Germany and lists her as the daughter of Johannes Weber and Marie Barbara Weber, and that she was born Janiary 1, 1819. But, another marriage record states she married Christina Wasser (misread by Ancestry.com) on October 24, 1840 in Freudenstadt, and that she was born January 1, 1819 and is the daughter of Johannes Weber and Katherina Dorothea Weber. The record for her second marriage, to David Friedrich Schweikert, states she was born January 1, 1819 and married November 24, 1850 in Freudenstadt; and that her parents are Johannes Weber and Catharine Dorothea Weber (the spelling of her mother's name in both records looks the same to me, but is interpreted by Ancestry.com and beginning with a "K" and a "C" respectively. I traced Marie Barbara Weber back in the records and found the Family Table for her marriage to Johannes (actually "Johan Jacob") Weber, and it does not mention any child named Agnes (there was an Ana Barbara born in May 1819) and none born in 1819. I have attached this Family Table to verify that the Agnes Barbara Weber who married David Friedrich Schweikert was not the daughter of Maria (Schnabel) Weber. Other than clerical errors in Germany, I have no explanation for the confusion, as the records seem to be related to the same person, but think the bulk of the evidience points toward her mother being Catherina Dorothea (EAD).
The Waldheim vs. Hancock Mutual Life Ins. Company case cited details that Christian Wurster (Jr.) took out a life insurance policy on himself with his wife Maria (also reported as "Marie" and "Marianna") as beneficiary. Maria died in January 1890 followed by Christian in April 1890, with the beneficiary not having been changed. In his will Christian specifically bequeathed the insurance money ($400.19) to his step-brother, William Schweikert. The deceased wife left no will. Apparently the plaintiff was Maria's son from a previous marriage, Albert Waldheim. This case clearly established the fact that Agnes (Barbara) Schweikert, nee Weber (as per German marriage records and her son William's marriage certificate) was the mother of Christian Wurster through her 1840 marriage (see the German marriage record) to Christian Wurster (Sr.). The case is available online via Google Books.