www.dpmsinc.com/10Expand.asp?ProductCode=UR-27A-NM

I noticed the small aperture is offset to the left so that when the aperture is flipped it retains the correct windage plane.  My question is, does anyone know if this is a same-plane aperture vertically/elevation-wise as well?

This being a NM sight leaf, why would you ever use the ghost ring?  It's not designed to be uses as a battle sight.  You would zero the rifle using the .052 aperature and go from there.

Who cares if it wasn't designed to be a battlesight?  Who cares what it was designed for if it fits my purpose?  That's like saying you can ONLY use an item for which it was designed and nothing else, no matter how many roles it may be capable of filling.  In that case, I hope you're not using your AR for anything but war, because it was NOT designed to be a target shooting rifle (although it fits this role just fine).

Of course I would zero using the small aperture.  The question is when I flip back to the GR, am I going to have to adjust elevation upward or are the apertures on the same verticle plane?

No, it's not on the same plane.  So yes, you will have to adjust for elevation.

I think Ashely Express has the only same plane sight leaf, but not nearly as small as the NM aperature.

Good luck.