The 0x383... one is some sort of short pants, the other one I haven't seen. They don't really cause big problems in your game. What they do is that they get assigned to the nude state of your sim, so he can wear them in the shower.
There are some early tattoos that were done this way so the first one could be just a tattoo (not listing those cause I feel the are ok categorized for nude).
The only problem with these is that they get packed with more sims then others cause you usually don't know that your sim is wearing them (cause you can't see that state in CAS).
There is a method to find out, what each package file actually is (at least what the Launcher pic looks like). It involves at least three third party tools and is not a fast method.
If you want to know, I will explain how to do it.
