The A388 F Apartment has a bench seat to accommodate two guests as per the seat belts provided. One has to therefore assume that you can use them.
Was OP Upped to First on the 388 recently and was placed BETWEEN a married couple ! I asked if there were opening slides (I knew that there were) and the stewardess said no. I then checked with the chef and he said of course so I then swapped seats around so that they could sleep next to each other. They were really grateful.
He by the way was a VERY well known 18 time world champion darts player
and VERY friendly