There's one on static display right next to Pegasus Bridge, near Caen, and it has the same marks.
Found this using google:
"The Centaur was specifically designed to act at D-Day, day one. It was used by The English Marine Corps. The pre-1943 brown colour was used, because it was thought to be better suited to the situation at D Day 1, the beaches. the degrees marks at the tower were applied to facilitate firing the howitzer, when still aboard at a LCT.
It was armed with a 95mm howitzer to destroy pillboxes.
The Centaur proved to be a valuable support weapon and was in effect used throughout the whole Normandy campaign and thereafter."
"The Centaur mounted a 95mm howitzer instead of the usual 75mm tank gun, and was employed as a fire support vehicle for artillery purposes. The Centaurs were used for firing from the landing craft as they approached the D-Day beaches. The markings on the turret are in fact degree marks to allow artillery observers to judge the bearing of the turret on a target from a distance.
The Centaurs were issued to the Royal Marines Armoured Support Group with the order to shell targets on the Normandy beaches, this they were more than happy to do.
They were also ordered to stay on the beaches because the Liberty engine fitted in the Centaur was none too reliable. However asking the Marines to stay out of a fight is like trying to stop the Earth from turning and they promptly got off the beach and headed inland to cause as much mayhem as possible!
The main difference between the Cromwell and the Centaur was the engine. The Cromwell had the Rolls Royce Meteor (derived from the famous Merlin Aero Engine), while the Centaur had the older (and less reliable) Liberty engine. The Liberty was employed because engine production was concentrated on aero engines, meaning that not enough Meteors were available. As Meteors became more plentiful, some Centaurs were converted by the addition of the more powerful Meteor engine."
