The 611H and 611HFM are virtually the same guitar; for the 'FM' models, the top (front) of the guitar has a flamed maple layer above the alder body. This banded wood is added purely for aesthetics and is only visible with translucent finishes. Therefore with a solid black finish, we use an alder guitar body which doesn't have a flamed maple top.
The hardware, pickups and configuration of the guitar are otherwise identical (and we think both look great!).