No, Geeklog does no such thing. The Classic theme is so simple that it works fine in most (if not all) browsers anyway.
When you say "Netscape" I assume you are referring to Netscape versions 4.x and their horrible support for CSS. Please note that Netscape 6 and 7 have excellent CSS support.
If you ever find yourself in need of different style sheets for Netscape 4 and the rest of the browsers, here's a simple trick that beats Netscape 4 with its own shortcomings: Make a simple style sheet that even Netscape 4 can understand. Then use the @import directive to include a more complex style sheet for the other browsers. Netscape 4 does not understand @import and will therefore ignore the complex style sheet.
Hope that helps.
bye, Dirk