The Mark IV is one of my favourites from the period too as the Cal. 1040 is such a good looking dial lay out. I used to have a Mark 4.5 ref 176.0016 (traded unfortunately) and loved it but seeing your mark IV makes me very jealous. The restoration has been wonderfully done and your dial retains a beautiful patina of the luminescence.
Wear it in good health and congratulations.
Zac