I know where that dou 43 is (Maroochydore)... :) It IS an RC, 100% (not all RC's have the X mark - I've owned more than 14 like this, many with NO RC X, some with a number at the woodline, some not even reblued).
$1600 is a little high for an RC even here, but they used to go $800 to $900 a...