That's what it sounds like to me. I once had a truck that went through 2 throw out bearings during the time I was driving it. Failures in the hydraulic clutch system was the culprit, as far as I was concerned. It only emmited that sound when the clutch pedal was depressed. Unfortunetly, when it happened to me, I was always several hundred miles from home. I was able to limp it home with clutchless shifting as much as possible. I also noticed a different feel in the pedal just before it "sounded off". Once the bearing fails it will grind the two races together whenever pressure is applied. I suggest you replace it as soon as possible.
I think you could get it out without removing the clutch. Just pull the trans and you should be able to get it out. I also recommend replacing the small pull back spring when you replace the bearing. It helps hold the bearing away from the clutch arms. If it doesn't pull fully away from the clutch it may continue to spin, which will shorten it's life.
Good luck,
Merle