Sheldon Brown to the rescue: http://www.sheldonbrown.com/chainline.html

I measure 55mm to the outer ring, and about 48 to the inner one. In other words, I am at least 5mm too far out. SO ... how could this work with the previous setup? If the spindle protrudes into the crank the same as before? My guess is that it never did - this bike had some bootleg parts on it and was generally unloved. I need to buy a Shimano retrieval tool and then will report back on the installation sans the spacer.