Hi Gary,
I haven't particularly studied the many variations in colon dot positions; in my experience the dot locations always vary a little bit from one die to the next.
I have acquired a nice 1853 Peck 1503, because it is a documented type, and have also noticed that 1851's (all OT's of course) have DEF colons at close, interim and far positions.
Below are examples of the close and interim on Gouby Style 2A (second 1 over 1), and Gouby Style 3 respectively.