Yes, Nick is right. It can be done.
However,
I would STRONGLY suggest that you make sure the limbs seat properly into the sockets.
ie.... The limb should essentially hit bottom (deepest part of socket) and seat easily.
If the limb needs to be "backed out" a little to seat properly, you run the risk of cracking the top of the socket. Not fixable if that happens.
The modern FF limb ends are shorter than Grayling limb ends and fitment is "questionable" most times.
If it were my setup, I would use grayling limbs in that handle. They will fit perfectly.
Good Luck........Philip