This is in the scene where Jackson, Mellisch (spelling?), and Reiben(spelling?) are checking to see if Ryan is on any of the dog tags. Watch when Capt. Miller has a handful and says, "he's not here." All but one of the tags are blank. when he drops them with the others, we can clearly see that many of the tags have not been engraved. Even if they had been upside-down, dog tag engraving comes out backwards on the back of the tags.