Nice! That shows the value of hi-res pictures. The first clue I saw in your first pics,
http://gallery.me.com/benhdvideoguy/...C_9865/web.jpg
was a tiny line on top of each pipe. But, it was hard to see if there was more.
I wasn't 100% sure, but the spec was another good clue.
That's why I asked you to dig in and look for the threads..
I've used a few 1/2" brass nipples and I always mark them up pretty badly..