The thing is, weapons officers can be normally good or normally bad, but it’s incredibly rare for them to do something extraordinary because their station doesn’t allow them much initiative.
It depends, honestly. There are nominations for awards given in the basis of an extraordinary achievment, even more so for higher awards, such as DSM and NC, and lower awards (bronze and silver stars) are given either for a long story of good service or minor achievments. NC and MV are given with a semi-official limit of one of each per campaign, but they’re not just given to the most deserving: there has to be something worth being nominated. Even since the institution of the award system (and that was two years ago), there was only one medal of valor, to Captain Corwin, who was the CO of the scout we had back then and developed many of the currently-accepted scout tactics.