Check out
http://sheldonbrown.com/vrbn-a-f.html#austro-daimler for some general info.
AD-Puch was a combined marque so you may have gotten a straight story from the seller. Generally, bikes labelled as AD were higher line than those sold as Puch but that's not always true. Are there any tubing decals on the seatpost? Better ADs used Reynolds 531 and such bikes were often Campy equipped.
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“Life is not one damned thing after another. Life is one damned thing over and over.”
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