nope,
not to any degree worth worrying about, it prety much see's there is no texture and goes, screw that noise, and move on to the next object, there is a small amount of over head involved with takeing care of offsets and orientations and the like, but it's nothing to realy worry about especaly because that is exactly what you are trying to use them for.
if you make sure to use the no colide invisable flag you also can probly not wory about them getting blown up.
you should also consiter the use of two lights glued together, that would be a slightly more elequient solution to your problem.