It's probably a GSAP (Gunsight aiming point) but a strange one, given the height, speed settings on the face of it. In the days of Sabres, Mirages, Macchis etc, a similar device was mounted on the top of the panel. The 'Pipper', the aiming point, was shown, via a collimator onto the glass, providing the pilot with the lead necessary for the relative speeds & angles between the combatants. It was an early form of HUD (head up display). The ones I'm familiar with were gyro controlled & the base unit was much thicker than the one shown, as the gyro was contained in the panel mounted device.
Other comments about gunship use might make sense in view of the speed & altitude setting controls, somewhat slower than the Sabres & Mirages of old.