Quoted:
You mean this one: https://danieldefense.com/rail-systems/omega-x-rail.html

It has a hole for a FSB so it would make the low profile seem unusual unless you have some sort of clamp on flip up sight.

Also when you say "fit over" can you clarify that a little? Do you mean will it slip over the barrel without having to remove the gas block because you have a pinned muzzle device? If that is what you meant, then no that is not the case. All of DD rails come with a special barrel nut that would require to you to remove the gas block, flash hider, and whatever barrel nut you have. I guess if you have a pinned muzzle device you could in theory install this provided the current barrel nut can be removed. Even if you already have the bolt up, the fact is you still need to remove the gas block tube because it goes through the handguard's ring.