Not really. And even if it looked nice, which frankly I'm not convinced it would, there's design issues with implementing a grid in-game. Adding fine, uniform detail like that may conflict with GUI elements, other objects, and generally make things less visually coherent for the player. I also don't believe a functionless grid right out of pop-SF fits with the fairly grounded, militaristic atmosphere of Freespace.
It's not a bad idea, but I completely oppose adding it to the retail campaign. If Volition wanted gridlines I'm sure they would have built them in.