You'll have to drill it then tap it for a bipod stud.

(assuming it does NOT have pre-drilled hole)

Mike

Yep - drill, then put a stud in like this one:
DPMS bipod stud for FF tubes

Looks like the bushamster FF handguard. I took mine to my local smith, he drilled tapped and threaded in a new stud. I think it cost me about $15.

Brownell's has a backplate that accepts a swivel stud after drilling a hole in the FF tube.  Swivel stud and backer are about $10 I think, it has more "meat" to it than drilling and tapping the tube.

Quoted: Yep - drill, then put a stud in like this one: DPMS bipod stud for FF tubes

i used one like that, hastnt moved in years.  just make sure the handguard is tight before you drill the hole or it wont be centered.

Harris Adapter Stud Swivel #5 AR-15 is for that purpose, that's what I used to mount a bipod on my FF tube.

www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=404111

Drilling and tapping can (and most likely will) create an indexing problem for the stud. You are better off using a lock nut on the inside of the tube and/or a backping plate designed for that purpose.

I'll also agree you want to be extremely sure that the freefloat tube is tight and that the hole is properly centered in the tube or you will find your rifle permanently canted when on a bi-pod (unless you level the legs each time -a real PITA).  Given the height of the optics or iron sights above the bore on an AR, canting errors get to be pretty serious as the range increases.