I can give you a link to my historic gunsight package which is probably what was referenced. It also has gunnery manuals from WW2. There are country specific folders with the primary gunsights used by each country. Readmes are included to help associate each gunsight to a ride.
Unzip this package on your hard drive. For each
{gunsight.bmp} you choose to copy to the game's sights folder, also copy it's
{gunsight.mil }size control file. Or you wont like the outcome.
Play with the alpha slider to dim the gunsight. It will be less distracting but, when held over your target brighten up. Start at about halfway to the right. Helps unclutter the cockpit forward view.
Down Load Link ===>> http://www16.zippyshare.com/v/48694084/file.html