I have been having research done on my Filbert ancestors by Dr. Igor Pleve of Saratov, Russia. He has found birth records for a Peter Filbert, shown as 1 December 1901, in Alt-Schilling. He was reported to have married a Theresia Luft, (shown as born 29 September 1902 in Baku town (not sure of the spelling, here). They were reported to have had 3 children (Olga, born 7 May 1925,Lydia, born 1 July 1927 and Alexander, born 24 January 1930) before church records were no longer continued.
The closest record found of a Johann Georg Filbert was of one born 12 May 1895 in Alt-Schilling to Jacob Filbert and Elisabeth Catharina Maul. This Johann Georg is shown to have married a Maria Harres in Alt-Schilling on 27 November 1924.
Dr. Pleve did find the David Filbert, born in Alt-Schilling on 5 June 1895. His parents are shown as Johann Conrad Filbert and Eva Maria Harres. He is shown to have married Maria Schreiber 6 March 1918. Their children were reported as David, born 11 January 1919; Alexander, born 16 June 1920, another Alexander, born 2 January 1922, Johannes, born 2 May 1924 and a third Alexander born 22 June 1926.