Thanks a bunch for posting those pics. Those show exactly what I wanted to know. No guessing now.
The following is cut and pasted from Magpul page on their Front MBUS. What is different about the offset sights?
NOTE: Cannot be mounted to a railed gas block due to excess heat issues.
Front MBUS must be mounted to a railed fore end on the same plane as the receiver rail. Because of this the sight is also not compatible with MOE Hand Guards.
Another pic I took with the mock rail sections from my packaging:
http://i.imgur.com/qrLmyFIl.jpg
Here's hoping for a LH set.
You had to release these right after I had bought a set of GG&G offset sights.
These look much better thought out than the GG&G's.