The difference between "procedural generation" and "random generation" is that with procedural generation, the "procedure" - the galaxy seed and the equations used to convert that seed into the in-game galaxy - will come up with the same answers, each time the equations are run. Think of it like the digits of pi. The digits of pi appear to the human eye to be "random", but they're not truly random, they're procedurally generated - run the equations for "calculate the value of pi" and you'll get the exact same answer, every single time, right down to the billionth-decimal-place digit of pi. You don't need to record the digits of pi down in a database somewhere, you can simply calculate them wherever and whenever you need them.
"Random generation" generates things differently each time you ask it to generate something.
Most things in the ED universe are procedurally generated, but there are some randomly generated things. "Non-persistent POIs" on planet surfaces - mineral outcrops, crashed satellites, wrecked SRVs and the smallest types of un-named installations - are randomly generated. Meaning that if you find a weird-looking crashed satellite on a planet's surface, park right in front of it, log off, and log back on again, the satellite will disappear.