I don’t know if “exact” would be really necessary, most games, if any, are not accurate if there is any collision/bounce off wall prediction.
Sometimes it’s just there to show you that if you throw it’s gonna hit the window, and the trajectory are just roughly right.
ie. games like Uncharted, Wolfenstien, etc. I am not familiar with Gears with later series, but aiming with trajectory is kinda pain in the butt. especially when you want to have a bounced grenade to land where you want.
Most of the time, the first hit location will be proper for AAA game, but for bounce hit location, not much.