I would take it as good, I see no reason to puncture an otherwise nice stamp.
Personally, I don't mind these types of examples
Early (only 100 years after the American revolution)
Plate position ID
Official Stamp, and at 4d possibly official correspondence going back to old Blighty
That stamp would have had a colourful career, been on a barque possibly
under canvas, sailing the seas.
Has enough history to stand alone on an album page.
Frematle (Swan River Colony) during your stamp
The first 75 convicts arrived in 1850 on the 'Scindian' from Portsmouth to be followed by over nine thousand more convicts before 1868.