Oil exposed to air can start to go bad after a month or so exposed to oxygen. So if your coffee beans have visible oil, they’ll be slightly more likely to taste worse sooner, just because the oil’s right there on the surface. But it doesn’t necessarily mean anything negative otherwise. If it helps, think of it like butter: you can reasonably leave a stick of butter on the counter for a while, and then it doesn’t taste as good anymore. Coffee is the same way, oil or not :)