This is relevant to those people who are worried that having multiple level 10's messes up your chance of getting Guild Marks for the class you want.
Apparently, a Leve has a particular set of Guild Marks on it during the random creation of the leve, they are just hidden from view if you don't have the right class up to the right level.
The reason I figured this out was I had a L9 gladiator about two kills from level 10. Leves had just reset and I checked them ALL for Pugilist marks (which is my main class). Then I went and dinged 10 on gladiator and went back to town. I happened to check the leves again and one of the leve's that previously had no guild marks on it now showed gladiator marks as a reward.
This was the same leve during the same reset. The gil reward was the same, the only thing that changed was the "hidden" guild mark reward was now revealed.