In those excellent photos, I could be mistaken but when chequer plate is painted the paint does seem to come of in well used areas and I think there a faint indications of it,
the crewman cleaning the barrel, in his shadow there appears to be spots at regular distancing where paint may be missing, and in other areas to his left going back towards the gun.
The plating on the left in the next picture seems to have very faint lines parallel to the plate again suggesting chequer.
The last picture again seems to indicate faint parallel lines on the decking.