Re: M40A3 S&B Scope
I don't know the model number but the civilian version is called the 3-12X50 Military. Basically what you are looking for is a 3-12X50 w/ 0.1 mrad More Tactile Click knobs in CCW configuration and an illuminated reticle. Issue S&B's (M8541) have a Gen II Mildot reticle however since the split I believe the best you can hope for now is a P4 Fine reticle.
I have some experience with the S&B 3-12 and I consider it one of the finest military optics available. It's compact, rugged, the adjustments are dead on, and what else is there to say other than it's a quality optic, which is pretty typical for S&B.