I´ll answer your wink with a serious analysis. ;)
It depends on the lore really. My impression is that skeletons are supposed to represent the long dead, rather than the more recently deceased. Since these are human land, it seems unlikely for there to be ways to get access to old Orc corpses from crypts and such, so you could leave skeleton Orcs out if you wanted to.
It depends on how you want to rationalise it though. You could say that the bodies from previous Orcish invasions might be around, though you could also reason that the humans would have burned them or otherwise gotten rid of them. So they could add them if they wanted to, but of the two more wïedergangers would be the more important pick.
