Yep, those items are sort of SOP when you get a new trailer. As far as I'm concerned they should throw away every drill/driver that those nitwits use and make them use screwdrivers until they know what a screw feels like getting tight.....not just run the drill until you get tired of it spinning then everything falls off.
Keep digging around and I'm sure you'll find more "stuff". Just in the belly of mine a couple of days ago and found a discarded sheet of luan about 2'x3' and a handful of dish rags in there??
Told DW I'm going back in there in a day or 2 and surely I can find some tools or lost change in addition to all the screws, metal strips/shavings etc. - sort of like a treasure hunt!