afaik, yes.
It's 40.000uF caps on a single rectifier, 2 outputs for power but these are parallel.
Don't know about the DC protection. There's 2 different inputs, but I guess it can be used for a single channel.
BTW, it's an expensive PS for single channel use!
You could use one PS for three channels (with possible loss of rail voltage for 3 channels fully used I guess) and add a switch to disengage one channel if not needed (I suppose you are doing an L-C-R setup?)
With one PS you are losing the ability for DC protection on one channel. You might add a cheap velleman 4701 for the centre channel but it is a passive device, I'm not sure it would do any good in case of DC on the center channel (relay will reset if the DC is gone - if it's "pulsating", don't know what it will do, or if it is fast enough for saving the C channel)
On & Off is a single connection on the PS, so you can switch the modules, no problem.
I'm going stereo with the HG PS, and might add a third channel in the way described, with a velleman DC protection, while the PS is doing the DC protection for L & R (my center is smaller and less power hungry, also cheaper than L&R) - for pure stereo I'll make sure it can be switched off.
Another possibility is to buy a standard grade PS for center. Don't know if it is a good thing to put 2 PS on a single set of secondaries though...