both of mine seem to have a small hole in the dead center - when i put it back on after bleeding my brakes - a bit of brake fluid squirts thru the cap -- is this normal ??

Mine has a small hole in it too. It must be a vent hole. If you get some out of it, I would say you may have too much fluid in. As a side note, my resevior has no hose for overflow....It has a place for one, but it is not tapped for a hose. I remember my '73 having a overflow hose, or am I wrong?

I had this problem with a 19mm master cyllinder I bought new from PelicanParts, but it was the pressed cap type thing, not a "hole". I called them, and they sent out a brand new one right away. The new one was bone dry 11 years ago, and still was today when I bled the brakes to change my fluid today. I would replace it if I were you.