The important thing to realise about this excellent war-time short story is the way that characters are defined by what they carry. Clearly, apart from the army regulation equipment that they have to carry, every item is the result of a choice that the soldiers have had to make bearing in mind the lack of space that they have and the added weight it will involve. Thus the objects that are personal to them are hugely significant in terms of what is important to them and how they define themselves. Note what the text tells us about this process of carrying, or "humping":
To carry something was to hump it, as when Lieutenant Jimmy Cross humped his love for Martha up the hills and through the swamps. In its intransitive form, to hump mean to walk, or to march, but it implied burdens far beyond the intransitive.
Thus each object also signifies a sort of psychological burden as well as a physical one, and you would do well to bear that in mind when you consider the importance of the objects each soldier carried.
Jimmy Cross thus carried his letters from Martha. Henry Dobbins carried extra rations. Dave Jensen carried a toothbrush, dental floss and soap and extra socks and foot powder. Ted Lavender carried tranquilizers and dope. Mitchell Sanders carried condoms. Norman Bowker carried a diary. Rat Kiley carried comic books. Kiowa carried an illustrated New Testament and a hunting hatchet. We are also told that nearly all of them carried photographs.