Ive just picked up a BushMaster XM15 E2S with a 20 inch barrel and it had a rail for accessories in the bottom hanguard. It was easy getting the rail off, just used an allen wrench. There are 3 studs in the handguard for hanging the rail system on the gun. Do you have to take the handguards off to remove those studs. Are they part of the rail system or something extra. Im going to be selling the rail system and a few other items I dont want, but I want the accessories rail to be complete. I'll list them in the Sell/Trade section tomorrow. Below is a photo of the rail and the other items Im going to sell. Im still new to ARs so Im not real knowledgeble about the accessories......  

From the rails I've seen in the past, similar to yours, the handguard must be removed. After the handguard is removed, remove the heat shield and pop out the threaded inserts.

Both the rail and the studs are add on - not standard fare.

Thanks guys, it was a piece of cake, no problem at all.