Probably dang near everyone. I have bought several different brand filter over the years and for whatever reason I wipe the base of the filter where it meets the engine with a shop rag before installing as a habit. I have seen a greasy grey residue on a lot of them. I just assume it is oil from the machining process which probably keeps them from rusting in shipping and storage. Probably a littleCan't blame storage rot. I wonder how many filters come with crud inside like this, but most of us never check (I don't)? Ignorance is bliss?
metal material in there as well. I have had engines go 300k or more, so I think there are a lot of other things in life to worry about.