Suspension Fork Maintenance?

My bike has its original suspension fork from 2004/2005 (the bike is a 2005 model but could have been assembled in late 2004). It's a Marzocchi MZ Race with 10cm of travel. It is clean, the spring-ring dust covers for the stanchions are in good condition and the fork suspends well.

The top of each stanchion has a large diameter hexagonal nut for adjusting. The bottom of each slider has a hex bolt.

Are suspension forks things that should be disassembled, cleaned and relubricated from time to time? I doubt these forks have been maintained. I don't see an air or oil port - is it likely these are spring-loaded only and have no air or oil?

I am a newbie with suspension forks, so any help is appreciated. I have been looking up information online, but maybe I could be steered in the right direction by experts here.

Not to worry - I haven't done anything to the forks yet!