If FE means Fast Ethernet, the answer is yes for the PCI-based models (220, 330 & 540). You need software release 4.X to support full duplex.
We're running 4.0.1c with 2 100tx-fd cards plugged into a cisco cat 5000. The ports on the cat are set to auto detect 10/100 half/full duplex but they keep deciding the toaster's interfaces are half duplex, any ideas?