All I know is that OMS stands for One Man Smokes. And the chap responsible for them used to have a YouTube channel with some good videos. Especially good were the ones where is visits tobacco farms and films the process.
I think they are factory pipes, although it's just an assumption and they look pretty well made for the money to me and I have never heard anyone complain about them. I think it is a similar thing going on as the Dagner pipes. In fact, I think they are friends.
Having said that I have never held one in hand or smoked one so probably should not really comment on them. They are not priced crazily so I would say if you fancy it go for it and you tell us what you think ;-)