We had a SWO attached to our company for a while. I don't remember what he did though.
A
SWO? Well, unless you were in an ANGLICO company (they used to have some SWOs for NGFS-type stuff, though I didn't think they did that anymore), I can't think of what he would have been doing there. Might be he was medical or supply and had an equivalent Surface pin - they look damn near identical unless you look close. Or he was an ex-SWO doing something different now. Or he was a SWO attached to some CENTCOM joint and just passing through the company for some purpose.
I'd be 99% sure he wasn't on an IA, though. The only IA's I've ever heard of were to Army units, joint staffs and every once in a very great while, a dirtside Air Force unit. Never Marines. They've got plenty of their own Navy dudes without asking for augmentation, as you well know.