Hello Joe, it does pivot forward for on and aft for off, and it does lock the bolt. I prefer it to the 21 left side safety as I find it easier and quicker to push fore and aft from the right than I do pushing the 21 left side unit up and down.
That said, the 21 unit is tidier and cleaner in aspect, I would generally say that the 21 unit doesn't lock the bolt but I had a 1956 unit that did by virtue of a small screw in the back of the unit that added this facility.
With Brno there is nothing set in stone and no absolutes.
Regards.
