The most reliable reference is given here:
viewtopic.php?t=35107&start=20Scroll down to
AUSTRIAN MARKS – 10
Pay attention to No. 58 and No 60. Number 58 (slightly different from Number 60) was used since 1872
(``seit 1872``). Number 60 was used since 1891.
Town marks were added the same year when they were added to Diana`s head, i.e. in 1872.
So far I have only seen AV (in hexagon) without the additional letter
Do you mean on silver or depicted elsewhere? If on silver, I would like to see images of the mark, because even Diana`s head without town mark is seldom seen. If you are referring to depicted marks, let’s not forget it`s often depicted as ``plain`` with a dot indicating the position of town mark.
If you look carefully there are dots here, too:
http://www.925-1000.com/Faustria_02.htmlBahner; thank you for Handelsverkehr