They will fit, just tight, which is good.
Take the lower half of the handguard and start to slip the VFG on the REAR area. Sit down on a carpeted area and hold the handguard half straight up and down, with the VFG pointed back towards you, between your knees, with the front of the handguard down. With the palm of your right hand reseting on top of the VFG, use your fingers to hold the lock open on the right side and your left hand/fingers to hold the left side lock open.
Now "hammer" the handguard into the carpet and the the VFG should slowly drift on the rail. I have used this method several times and it works like a charm. You can also wedge a toothpick or other item into the locks to "hold them open" while you "tap" the grip down the rails.
By "hammering" into the carpet, you don't cause any damage to the handguard or leave any nasty marks.
Actually, I got pissed off and tried this to find that it worked perfectly.