Interesting phrase, that. You can tell an awful lot about a wargamer by what <X> is and/or what is implied by <X>. (Tongue firmly planted in cheek here, note...)
See, sometimes, <X> can be "<system> <force>", for example '40K Tyranid army" or 'Flames of War SS army' (or "Bolt Action Russian army" these days, I suspect!). (The system is often implicit or obvious from context.) And you can pretty much guarantee from that that the army is mini-maxed to within an inch of its life, and the owner probably thinks of it as a single entity. I remain slightly boggled by (for example) people I see selling a very specific FoW army who I know are moving to some other WW2 ruleset... Uh... hello? Ever considered you might need some of those vehicles or infantry...?
Sometimes, <X> can be "<force> (based for <system>)". It's a racing certainty that the force is historical. It's probably also a halfway decent bet that they haven't mini-maxed it (with the possible exception of things based for WAB and its children) because their ruleset doesn't do points in that way.
Sometimes, <X> can be "<force> <organizational unit>" ("DAK infantry company", say.) This is the next step up from the previous. Pretty much guaranteed historical, definitely not mini-maxed. And tells you that the owner cares more about the historical force balance than the system, is very likely more into playing scenarios than head-to-head points-balanced scraps, and is prepared to work round basing issues if it gets them a game :D
Have I missed any?
Is it safe? (It's James' birthday and I'm tucked away in the office from a houseful of 14 year olds armed with Nerf guns).