OK, so basically, it doesn't matter at all, compared to the rest of the load.
If you want to further optimize it... with glBegin() and color values, you can speed that up with display lists (IDK if you're still wanting to try doing ship borders but that'd definitely have to involve display lists to be fast), with missiles you can probably do a sort of friendly and enemy in an array and then use a display list with pre-built color values; the only operations you have to do in glBegin at that point is scale, position, rotation and calling the list, because the glColor values can already be done in the display list instructions.
That said, I doubt if any of that is actually necessary, let alone doing more esoteric stuff, like using VBO to do more of the work on the GPU
Anyhow, I am really looking forwards to putting this in with Vacuum, where the scale of the battles is such that having this would be a huge thing