If you are flying one of the models of Albatross, there in NO front gunsite, there never was. The bullet's Point Of Impact, would naturally be between the two guns, yet elevated quite a bit, like the top of the windscreen on the DIII, or along the water tank fill neck on the DII
If you're sighting along the barrels themselves, you would be hitting the air ABOVE your target
Best way to determine your Point of Impact. Would be attack a tree, or a shoreline, someplace where you can see the hits, as you kickup some dust or plumes of water