I did a quick check of the tire & couldn't find the spot. I'll check again more carefully.
I think Merlin's advice agrees w/McCready - that you should be able to lock both wheels if needed.
It's hard to imagine with that much weight transferrence that one could lock the front wheel. Also, I don't think I have the guts to try it and I'd likely have to replace the front tire afterwards.
Anyone ever locked the front wheel on purpose or otherwise?