Mine was the 'fixie' version, stickered up and everything and was supposedly for use with rear brake and came with the little hole that you have. I assumed it was a pilot hole intended to be drilled out for a brake (which is what I did). I figured the 'track' version not for use with a brake would have had no hole in the bridge at all. I've never before seen a 464 like the 2nd one you've posted.
Mine was the 'fixie' version, stickered up and everything and was supposedly for use with rear brake and came with the little hole that you have. I assumed it was a pilot hole intended to be drilled out for a brake (which is what I did). I figured the 'track' version not for use with a brake would have had no hole in the bridge at all. I've never before seen a 464 like the 2nd one you've posted.