Just checked on MacTracker -- yes, the 5,5 Pro had firewire; it's immediate predecessor was the Macbook (no pro) 5,1, which didn't have FW but had the removable battery -- the 5,5 added Firewire.
Oh yeah, I'd forgotten about that aluminum Macbook (sans pro). I was working in a multimedia lab at the time and we were pretty dependent on firewire for student projects and putting the Macs into targeted disk mode.