I picked up another set of Krink handgards and the lower HG is a little different and appears to be modified.  The darker HG's on the right are stock and came w/my demilled kit.  The lighter HG set on the left has part of the wood cut away on the lower part of the HG.  Will this affect the fit or do i need to try and send these back?? If this area doesnt affect anything, why would someone have done this modification??  

It looks like the handguards on the left have been modified (trimmed) to fit a milled receiver gun. They can be made to work on a stamped receiver gun if you glue a small block of wood or plastic to build up the ledge that goes into the receiver to the original thickness. It won't show once they're mounted.

Quoted: It looks like the handguards on the left have been modified (trimmed) to fit a milled receiver gun. They can be made to work on a stamped receiver gun if you glue a small block of wood or plastic to build up the ledge that goes into the receiver to the original thickness. It won't show once they're mounted.

+1....but you might wanna slope the top piece that you add so that it won't come off during insertion.

I'm going to have to make a similar modification once my build is done.  I'm guessing that there is a dimensional difference between my NDS receiver and the original. Obviously, the tunnion hasn't changed.