I'm no expert on British practice for ship deck coverings. An answer in this case is more complicated because this was a USA-built ship, loaned to the UK, and then returned to the USA. In this photo and according to the history I found posted below, she made at least two voyages under the "UK flag". I assume that after delivery to the UK, they made mods to the ship to suit their practices. I have found references to brown corticene (a rough surfaced linoleum), held down with shiny brass strips being used early in WWII on British warships. But, what was used on British Merchant ships, I have no idea.
There seems to be a mystery as to why SS EMPIRE FULMAR is seen flying a Royal Navy Ensign. There could be more to her story and use in the RN than we know??? I find the appearance of SS EMPIRE FULMAR to be very clean. Most merchants ships during WWII look rather messy with deck cargo, etc. I wonder if she was used for high priority cargo because of her relatively fast speed? Or if she was on a special mission during her first operational voyage under the RN Ensign transporting ranking RN personnel???