Yes, the latest Firefox has hundreds of security features that are missing in Netscape, and more are added with each update as new exploits and bugs are discovered.
Netscape Communicator 4.8 theme:
https://addons.mozilla.org/en-US/firefox/addon/4083
Netscape 3.1 theme:
https://addons.mozilla.org/en-US/firefox/addon/3471
Click the Add To Firefox button, then restart Firefox when it has finished installing. It will just take a few seconds.
There's also a newer theme called Netstripe that makes Firefox look like Netscape 9, but the links I tried were all dead.