The ones on the CG 1.0 are pretty high detail... As far as roundness goes, they actually have more segments than the outer edge of the saucer. They were originally lower detail, but several of the polygon joints stuck out in a few places, and I just chamfered the entire set so it would look even, rather than rebuilding them to be more efficient.
That's been fixed on my latest version, but I think the high detail ones might seem out of place on this model. Not overly so, but they will boost the polycount by a good amount if used.
You're welcome to do it if you want, but if you want extra practice modeling, making new phasers would be good for that. They're pretty quick and painless to do, but they use skills that are pretty universal in 3DS Max. ;)