Right, aside from signs of physical damage to the drivers or the enclosure, just listen to them.
Physical damage with new speakers is rare, but would likely be form being dropped from some distance, which obviously would damage the box they came in pretty obviously, so you'd want to look for superficial damage. And obviously there shouldn't be anything shaking around inside. Usually it would be something like the crossover components coming loose from a particularly bad shock or something. Rare.
If they're new, there really shouldn't be any reason for electrical issues, if they play fine they should be fine. You can always test the resistance of the speaker and see that it's not blown(shorted) but again if they're new this wouldn't be the case.
Plug them in, listen to them and they should sound great.
If there is something wrong, it is usually very and immediately obvious. And almost all speaker damage comes from abuse. Seeing as how they are new, you haven't even had the chance to abuse them...