I distinctly remember Starbuck showing them the Viper mk2 and saying that they've never flown anything like it "...so don't think you have". All the trainees were trained on the mk2's, showing them diagrams of a mk3 cockpit would be silly in two ways: 1) why show people the cockpit of a fighter version they'll never fly, since they're trained on the mk2's, and 2) showing a mk3 cockpit would mean they have to make the mk3 cockpit first. Just for that? What's the point, when they never show the mk3 viper and already have the mk2 ready?
Pretty sure you remembered it wrong. Nothing regarding the mk3 was ever seen in the show.