trancejeremy is right, (I'll just ad a little to what he said)
No, the FN F2000 is not like a OICW.
The FN (Fabrique Nationale - Belgium) Herstal F2000 is a bullpup (magazine behind the grip) design.
The Alliant (Alliant Techsystems - Alliant, US company, is making it jointly with Heckler & Koch, a Germany company, so it really is sort of European anyway even though it is being made for the US) SABRE or OICW (Objective Individual Combat Weapon) is based off of H&K's G36 series rifle, which has it's magazine in the front of the grip.
The FN F2000 has much more in common with Steyr's (Steyr-Mannlicher AG company of Austria) AUG (Armee Universal Gewehr - Universal Army Rifle), IMI's (Israel Military Industries) Tavor TAR-21, St-Etienne Arms Factory's (a member of the French government owned GIAT concern) FAMAS (Fusil d'Assaut de la Manufacture d'Armes de St-Etienne) and Enfield's (Enfield Small Arms Factory - British) L85A1, because of it's bullpup design.
The FN F2000 also like pretty much every other assault rifle (but the OICW) uses a single loading 40mm grenade launcher (if added), like the M203 Grenade Launcher for the M-16 or HK79 (the German M203) or the AG36 (AG - Anbaugranatwerfer - "attached grenade launcher") for the G36, so if you fire once you have to reload before firing again.
The OICW uses a six shot (bullpup) magazine of 20mm Grenades (though it's not the only gun to use 20mm explosive rounds - most of the others are anti-material rifles that are not programmable to my knowledge) so it can fire again and again and again and again...
The grenades are computer control detonated and laser guided so they can explode on impact, behind a target, in front of a target, or even delay after impact.
The ability to detonate a explosive mid-air past a wall (effectively letting it fire around corners) along with it's being able to fire many explosive rounds in rapid succession is what gave it the 5-1 kill ratio need by the US testing.
The main design element of the F2000 is it's modular design for a compact controlled size (and it's very nice for this reason).
Many of the things like the electronic scopes and the grenade launcher are made to be easy added or taken off depending on the situation, they are part of it not an after thought piece.
So if you don't really need a piece you don't need the extra weight (it's also cheaper if you don't need the extra parts), also the design (the handles most of all) take alot from the compact FN P90 design (my favorite gun) which is very ergonomically made for a high amount of control in a compact automatic weapon.
Most bullpup designs are not ambidextrous but the F2000 is because it's based off the P90.