[luigi bertolotti]

The "convertd" IIICs are not rare. but not even common... it was a standard listed "upgrade"... was carried on at the factory... I'd say they are treated, in the collectors market, like other originals item of that timeframe, with value most depending on conditions; I think some original Leitz paper which states the date of the upgrade of that camera, identified by s/n, would be a significative add-on value.