OK, so here's the scoop:
The bike originally was built by a shop owner in CT who was into all the high end mtbs during the early 90's. He was known for replacing parts on his bikes with the latest and greatest...titanium bolts, springs, anno chic parts, etc...
The fork mod was done by him during the build of the bike as part of a ti spring kit. With the elastomers gone, a large air space now existed, which created internal pressure during compression between the lower wiper seal and the upper top cap o-ring, causing the caps to pressurize. The zirc fittings and tubes act as a pressure relief valve of sorts, allowing air to escape during compression and light oil to be introduced occasionally to keep the springs quiet.