Information provided by Magnum Research. They said this was all they have from BUL.

From looks of it, a 1911 type rear sight Novak style should fit as long as it's a 65deg angle, it'll just need to be filed down to the .466 width as many are sold as .495 width.

Anyway, hope this helps. I found a Springfield adjustable rear sight that should fit, just ordered and will report back. From looks of it there's no real room to add a lower front sight but probably easy to add a higher front sight if you need to lower POI.

***** I can't post attachments for some reason, maybe I'm too new to this forum. DM me for the attachmemts.