The 520 has been in Trek's line since the stone age with very little change. The current frame has a sloping top tube instead of a level one but I believe all the other geometric considerations are very close to the same so the fork crown-axle and rake dimensions are probably the same as the current bike.
BTW, here is a .pdf of the 1995 Trek catalog covering the steel frame bikes from that year, including the 520. Scroll down to the bottom of page 7 for a chart of the 520's geometry and compare it to the 2010 catalog info. They are very similar. Note, for example, the rake dimension is identical at 5.2 cm for both the 1995 and 2010 bikes.
http://www.vintage-trek.com/images/trek/95/Trek95.pdf