The other day when we had 162 and the nits were furiously trying to get it back the SB was manned, and many thought it was not firing until I started to circle above the CV. I could see the splashes of the rounds landing just shy of the CV. I gave feedback to the SB about where the shells were landing and the accuracy improved.
Just because you cannot see or hear it firing does not mean it isn't

but still it would be nice to have an icon above guns so you don't have to say "Hey you in the shore battery over the town", or "The guy in the field ack, on the southern end of the runway", and so forth...