"You may cast that card" confusion

[ronco]

Take two cards that let you cast something from a non-hand zone, Mission Briefing and memory plunder. Memory plunder allows you to cast the card upon resolution ignoring timing effects (ie sorcery on an opponents turn) while mission briefing does not.

Is the difference on these types of cards due to the "casting upon resolution" (Memory Plunder) vs "casting this turn" (Mission Briefing)? How can I tell effects like this apart without going to gatherer in the future?

[H]

I'm fairly certain that if the card gives you no duration during which you can cast it, it is cast upon resolution. If it has a duration, than normal timing restrictions apply and it must be cast within that duration or not cast at all.

[ronco]

Thanks!